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LU-12093 osc: don't check capability for every page
[fs/lustre-release.git] / lustre / osc / osc_cache.c
1 /*
2  * GPL HEADER START
3  *
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 only,
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License version 2 for more details (a copy is included
14  * in the LICENSE file that accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License
17  * version 2 along with this program; If not, see
18  * http://www.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2012, 2017, Intel Corporation.
27  *
28  */
29 /*
30  * This file is part of Lustre, http://www.lustre.org/
31  * Lustre is a trademark of Sun Microsystems, Inc.
32  *
33  * osc cache management.
34  *
35  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
36  */
37
38 #define DEBUG_SUBSYSTEM S_OSC
39
40 #include <lustre_osc.h>
41
42 #include "osc_internal.h"
43
44 static int extent_debug; /* set it to be true for more debug */
45
46 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
47 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
48                            enum osc_extent_state state);
49 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
50                               struct osc_async_page *oap, int sent, int rc);
51 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
52                           int cmd);
53 static int osc_refresh_count(const struct lu_env *env,
54                              struct osc_async_page *oap, int cmd);
55 static int osc_io_unplug_async(const struct lu_env *env,
56                                struct client_obd *cli, struct osc_object *osc);
57 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
58                            unsigned int lost_grant, unsigned int dirty_grant);
59
60 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
61                                   const char *func, int line);
62 #define osc_extent_tree_dump(mask, obj) \
63         osc_extent_tree_dump0(mask, obj, __func__, __LINE__)
64
65 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
66                                 unsigned int unused);
67
68 /** \addtogroup osc
69  *  @{
70  */
71
72 /* ------------------ osc extent ------------------ */
73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
74 {
75         char *buf = flags;
76         *buf++ = ext->oe_rw ? 'r' : 'w';
77         if (ext->oe_intree)
78                 *buf++ = 'i';
79         if (ext->oe_sync)
80                 *buf++ = 'S';
81         if (ext->oe_srvlock)
82                 *buf++ = 's';
83         if (ext->oe_hp)
84                 *buf++ = 'h';
85         if (ext->oe_urgent)
86                 *buf++ = 'u';
87         if (ext->oe_memalloc)
88                 *buf++ = 'm';
89         if (ext->oe_trunc_pending)
90                 *buf++ = 't';
91         if (ext->oe_fsync_wait)
92                 *buf++ = 'Y';
93         *buf = 0;
94         return flags;
95 }
96
97 static inline char list_empty_marker(struct list_head *list)
98 {
99         return list_empty(list) ? '-' : '+';
100 }
101
102 #define EXTSTR       "[%lu -> %lu/%lu]"
103 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
104 static const char *oes_strings[] = {
105         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
106
107 #define OSC_EXTENT_DUMP_WITH_LOC(file, func, line, mask, extent, fmt, ...) do {\
108         static struct cfs_debug_limit_state cdls;                             \
109         struct osc_extent *__ext = (extent);                                  \
110         char __buf[16];                                                       \
111                                                                               \
112         __CDEBUG_WITH_LOC(file, func, line, mask, &cdls,                      \
113                 "extent %p@{" EXTSTR ", "                                     \
114                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
115                 /* ----- extent part 0 ----- */                               \
116                 __ext, EXTPARA(__ext),                                        \
117                 /* ----- part 1 ----- */                                      \
118                 atomic_read(&__ext->oe_refc),                                 \
119                 atomic_read(&__ext->oe_users),                                \
120                 list_empty_marker(&__ext->oe_link),                           \
121                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
122                 __ext->oe_obj,                                                \
123                 /* ----- part 2 ----- */                                      \
124                 __ext->oe_grants, __ext->oe_nr_pages,                         \
125                 list_empty_marker(&__ext->oe_pages),                          \
126                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
127                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
128                 /* ----- part 4 ----- */                                      \
129                 ## __VA_ARGS__);                                              \
130         if (mask == D_ERROR && __ext->oe_dlmlock != NULL)                     \
131                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
132         else                                                                  \
133                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
134 } while (0)
135
136 #define OSC_EXTENT_DUMP(mask, ext, fmt, ...)                            \
137         OSC_EXTENT_DUMP_WITH_LOC(__FILE__, __func__, __LINE__,          \
138                                  mask, ext, fmt, ## __VA_ARGS__)
139
140 #undef EASSERTF
141 #define EASSERTF(expr, ext, fmt, args...) do {                          \
142         if (!(expr)) {                                                  \
143                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
144                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
145                 LASSERT(expr);                                          \
146         }                                                               \
147 } while (0)
148
149 #undef EASSERT
150 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
151
152 static inline struct osc_extent *rb_extent(struct rb_node *n)
153 {
154         if (n == NULL)
155                 return NULL;
156
157         return container_of(n, struct osc_extent, oe_node);
158 }
159
160 static inline struct osc_extent *next_extent(struct osc_extent *ext)
161 {
162         if (ext == NULL)
163                 return NULL;
164
165         LASSERT(ext->oe_intree);
166         return rb_extent(rb_next(&ext->oe_node));
167 }
168
169 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
170 {
171         if (ext == NULL)
172                 return NULL;
173
174         LASSERT(ext->oe_intree);
175         return rb_extent(rb_prev(&ext->oe_node));
176 }
177
178 static inline struct osc_extent *first_extent(struct osc_object *obj)
179 {
180         return rb_extent(rb_first(&obj->oo_root));
181 }
182
183 /* object must be locked by caller. */
184 static int osc_extent_sanity_check0(struct osc_extent *ext,
185                                     const char *func, const int line)
186 {
187         struct osc_object *obj = ext->oe_obj;
188         struct osc_async_page *oap;
189         size_t page_count;
190         int rc = 0;
191
192         if (!osc_object_is_locked(obj))
193                 GOTO(out, rc = 9);
194
195         if (ext->oe_state >= OES_STATE_MAX)
196                 GOTO(out, rc = 10);
197
198         if (atomic_read(&ext->oe_refc) <= 0)
199                 GOTO(out, rc = 20);
200
201         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
202                 GOTO(out, rc = 30);
203
204         switch (ext->oe_state) {
205         case OES_INV:
206                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
207                         GOTO(out, rc = 35);
208                 GOTO(out, rc = 0);
209                 break;
210         case OES_ACTIVE:
211                 if (atomic_read(&ext->oe_users) == 0)
212                         GOTO(out, rc = 40);
213                 if (ext->oe_hp)
214                         GOTO(out, rc = 50);
215                 if (ext->oe_fsync_wait && !ext->oe_urgent)
216                         GOTO(out, rc = 55);
217                 break;
218         case OES_CACHE:
219                 if (ext->oe_grants == 0)
220                         GOTO(out, rc = 60);
221                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
222                         GOTO(out, rc = 65);
223         default:
224                 if (atomic_read(&ext->oe_users) > 0)
225                         GOTO(out, rc = 70);
226         }
227
228         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
229                 GOTO(out, rc = 80);
230
231         if (ext->oe_sync && ext->oe_grants > 0)
232                 GOTO(out, rc = 90);
233
234         if (ext->oe_dlmlock != NULL &&
235             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
236             !ldlm_is_failed(ext->oe_dlmlock)) {
237                 struct ldlm_extent *extent;
238
239                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
240                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
241                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
242                         GOTO(out, rc = 100);
243
244                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
245                         GOTO(out, rc = 102);
246         }
247
248         if (ext->oe_nr_pages > ext->oe_mppr)
249                 GOTO(out, rc = 105);
250
251         /* Do not verify page list if extent is in RPC. This is because an
252          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
253         if (ext->oe_state > OES_CACHE)
254                 GOTO(out, rc = 0);
255
256         if (!extent_debug)
257                 GOTO(out, rc = 0);
258
259         page_count = 0;
260         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
261                 pgoff_t index = osc_index(oap2osc(oap));
262                 ++page_count;
263                 if (index > ext->oe_end || index < ext->oe_start)
264                         GOTO(out, rc = 110);
265         }
266         if (page_count != ext->oe_nr_pages)
267                 GOTO(out, rc = 120);
268
269 out:
270         if (rc != 0)
271                 OSC_EXTENT_DUMP_WITH_LOC(__FILE__, func, line, D_ERROR, ext,
272                                          "sanity check %p failed: rc = %d\n",
273                                          ext, rc);
274         return rc;
275 }
276
277 #define sanity_check_nolock(ext) \
278         osc_extent_sanity_check0(ext, __func__, __LINE__)
279
280 #define sanity_check(ext) ({                                                   \
281         int __res;                                                             \
282         osc_object_lock((ext)->oe_obj);                                        \
283         __res = sanity_check_nolock(ext);                                      \
284         osc_object_unlock((ext)->oe_obj);                                      \
285         __res;                                                                 \
286 })
287
288
289 /**
290  * sanity check - to make sure there is no overlapped extent in the tree.
291  */
292 static int osc_extent_is_overlapped(struct osc_object *obj,
293                                     struct osc_extent *ext)
294 {
295         struct osc_extent *tmp;
296
297         LASSERT(osc_object_is_locked(obj));
298
299         if (!extent_debug)
300                 return 0;
301
302         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
303                 if (tmp == ext)
304                         continue;
305                 if (tmp->oe_end >= ext->oe_start &&
306                     tmp->oe_start <= ext->oe_end)
307                         return 1;
308         }
309         return 0;
310 }
311
312 static void osc_extent_state_set(struct osc_extent *ext, int state)
313 {
314         LASSERT(osc_object_is_locked(ext->oe_obj));
315         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
316
317         /* Never try to sanity check a state changing extent :-) */
318         /* LASSERT(sanity_check_nolock(ext) == 0); */
319
320         /* TODO: validate the state machine */
321         ext->oe_state = state;
322         wake_up_all(&ext->oe_waitq);
323 }
324
325 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
326 {
327         struct osc_extent *ext;
328
329         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
330         if (ext == NULL)
331                 return NULL;
332
333         RB_CLEAR_NODE(&ext->oe_node);
334         ext->oe_obj = obj;
335         cl_object_get(osc2cl(obj));
336         atomic_set(&ext->oe_refc, 1);
337         atomic_set(&ext->oe_users, 0);
338         INIT_LIST_HEAD(&ext->oe_link);
339         ext->oe_state = OES_INV;
340         INIT_LIST_HEAD(&ext->oe_pages);
341         init_waitqueue_head(&ext->oe_waitq);
342         ext->oe_dlmlock = NULL;
343
344         return ext;
345 }
346
347 static void osc_extent_free(struct osc_extent *ext)
348 {
349         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
350 }
351
352 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
353 {
354         LASSERT(atomic_read(&ext->oe_refc) >= 0);
355         atomic_inc(&ext->oe_refc);
356         return ext;
357 }
358
359 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
360 {
361         LASSERT(atomic_read(&ext->oe_refc) > 0);
362         if (atomic_dec_and_test(&ext->oe_refc)) {
363                 LASSERT(list_empty(&ext->oe_link));
364                 LASSERT(atomic_read(&ext->oe_users) == 0);
365                 LASSERT(ext->oe_state == OES_INV);
366                 LASSERT(!ext->oe_intree);
367
368                 if (ext->oe_dlmlock != NULL) {
369                         lu_ref_add(&ext->oe_dlmlock->l_reference,
370                                    "osc_extent", ext);
371                         LDLM_LOCK_PUT(ext->oe_dlmlock);
372                         ext->oe_dlmlock = NULL;
373                 }
374                 cl_object_put(env, osc2cl(ext->oe_obj));
375                 osc_extent_free(ext);
376         }
377 }
378
379 /**
380  * osc_extent_put_trust() is a special version of osc_extent_put() when
381  * it's known that the caller is not the last user. This is to address the
382  * problem of lacking of lu_env ;-).
383  */
384 static void osc_extent_put_trust(struct osc_extent *ext)
385 {
386         LASSERT(atomic_read(&ext->oe_refc) > 1);
387         LASSERT(osc_object_is_locked(ext->oe_obj));
388         atomic_dec(&ext->oe_refc);
389 }
390
391 /**
392  * Return the extent which includes pgoff @index, or return the greatest
393  * previous extent in the tree.
394  */
395 static struct osc_extent *osc_extent_search(struct osc_object *obj,
396                                             pgoff_t index)
397 {
398         struct rb_node    *n = obj->oo_root.rb_node;
399         struct osc_extent *tmp, *p = NULL;
400
401         LASSERT(osc_object_is_locked(obj));
402         while (n != NULL) {
403                 tmp = rb_extent(n);
404                 if (index < tmp->oe_start) {
405                         n = n->rb_left;
406                 } else if (index > tmp->oe_end) {
407                         p = rb_extent(n);
408                         n = n->rb_right;
409                 } else {
410                         return tmp;
411                 }
412         }
413         return p;
414 }
415
416 /*
417  * Return the extent covering @index, otherwise return NULL.
418  * caller must have held object lock.
419  */
420 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
421                                             pgoff_t index)
422 {
423         struct osc_extent *ext;
424
425         ext = osc_extent_search(obj, index);
426         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
427                 return osc_extent_get(ext);
428         return NULL;
429 }
430
431 /* caller must have held object lock. */
432 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
433 {
434         struct rb_node   **n      = &obj->oo_root.rb_node;
435         struct rb_node    *parent = NULL;
436         struct osc_extent *tmp;
437
438         LASSERT(ext->oe_intree == 0);
439         LASSERT(ext->oe_obj == obj);
440         LASSERT(osc_object_is_locked(obj));
441         while (*n != NULL) {
442                 tmp = rb_extent(*n);
443                 parent = *n;
444
445                 if (ext->oe_end < tmp->oe_start)
446                         n = &(*n)->rb_left;
447                 else if (ext->oe_start > tmp->oe_end)
448                         n = &(*n)->rb_right;
449                 else
450                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
451         }
452         rb_link_node(&ext->oe_node, parent, n);
453         rb_insert_color(&ext->oe_node, &obj->oo_root);
454         osc_extent_get(ext);
455         ext->oe_intree = 1;
456 }
457
458 /* caller must have held object lock. */
459 static void osc_extent_erase(struct osc_extent *ext)
460 {
461         struct osc_object *obj = ext->oe_obj;
462         LASSERT(osc_object_is_locked(obj));
463         if (ext->oe_intree) {
464                 rb_erase(&ext->oe_node, &obj->oo_root);
465                 ext->oe_intree = 0;
466                 /* rbtree held a refcount */
467                 osc_extent_put_trust(ext);
468         }
469 }
470
471 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
472 {
473         struct osc_object *obj = ext->oe_obj;
474
475         LASSERT(osc_object_is_locked(obj));
476         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
477         if (ext->oe_state == OES_CACHE) {
478                 osc_extent_state_set(ext, OES_ACTIVE);
479                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
480         }
481         atomic_inc(&ext->oe_users);
482         list_del_init(&ext->oe_link);
483         return osc_extent_get(ext);
484 }
485
486 static void __osc_extent_remove(struct osc_extent *ext)
487 {
488         LASSERT(osc_object_is_locked(ext->oe_obj));
489         LASSERT(list_empty(&ext->oe_pages));
490         osc_extent_erase(ext);
491         list_del_init(&ext->oe_link);
492         osc_extent_state_set(ext, OES_INV);
493         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
494 }
495
496 static void osc_extent_remove(struct osc_extent *ext)
497 {
498         struct osc_object *obj = ext->oe_obj;
499
500         osc_object_lock(obj);
501         __osc_extent_remove(ext);
502         osc_object_unlock(obj);
503 }
504
505 /**
506  * This function is used to merge extents to get better performance. It checks
507  * if @cur and @victim are contiguous at block level.
508  */
509 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
510                             struct osc_extent *victim)
511 {
512         struct osc_object       *obj = cur->oe_obj;
513         struct client_obd       *cli = osc_cli(obj);
514         pgoff_t                  chunk_start;
515         pgoff_t                  chunk_end;
516         int                      ppc_bits;
517
518         LASSERT(cur->oe_state == OES_CACHE);
519         LASSERT(osc_object_is_locked(obj));
520         if (victim == NULL)
521                 return -EINVAL;
522
523         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
524                 return -EBUSY;
525
526         if (cur->oe_max_end != victim->oe_max_end)
527                 return -ERANGE;
528
529         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
530         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
531         chunk_start = cur->oe_start >> ppc_bits;
532         chunk_end   = cur->oe_end   >> ppc_bits;
533         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
534             chunk_end + 1 != victim->oe_start >> ppc_bits)
535                 return -ERANGE;
536
537         /* overall extent size should not exceed the max supported limit
538          * reported by the server */
539         if (cur->oe_end - cur->oe_start + 1 +
540             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
541                 return -ERANGE;
542
543         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
544
545         cur->oe_start     = min(cur->oe_start, victim->oe_start);
546         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
547         /* per-extent tax should be accounted only once for the whole extent */
548         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
549         cur->oe_nr_pages += victim->oe_nr_pages;
550         /* only the following bits are needed to merge */
551         cur->oe_urgent   |= victim->oe_urgent;
552         cur->oe_memalloc |= victim->oe_memalloc;
553         list_splice_init(&victim->oe_pages, &cur->oe_pages);
554         list_del_init(&victim->oe_link);
555         victim->oe_nr_pages = 0;
556
557         osc_extent_get(victim);
558         __osc_extent_remove(victim);
559         osc_extent_put(env, victim);
560
561         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
562         return 0;
563 }
564
565 /**
566  * Drop user count of osc_extent, and unplug IO asynchronously.
567  */
568 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
569 {
570         struct osc_object *obj = ext->oe_obj;
571         struct client_obd *cli = osc_cli(obj);
572         int rc = 0;
573         ENTRY;
574
575         LASSERT(atomic_read(&ext->oe_users) > 0);
576         LASSERT(sanity_check(ext) == 0);
577         LASSERT(ext->oe_grants > 0);
578
579         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
580                 LASSERT(ext->oe_state == OES_ACTIVE);
581                 if (ext->oe_trunc_pending) {
582                         /* a truncate process is waiting for this extent.
583                          * This may happen due to a race, check
584                          * osc_cache_truncate_start(). */
585                         osc_extent_state_set(ext, OES_TRUNC);
586                         ext->oe_trunc_pending = 0;
587                 } else {
588                         int grant = 0;
589
590                         osc_extent_state_set(ext, OES_CACHE);
591                         osc_update_pending(obj, OBD_BRW_WRITE,
592                                            ext->oe_nr_pages);
593
594                         /* try to merge the previous and next extent. */
595                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
596                                 grant += cli->cl_grant_extent_tax;
597                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
598                                 grant += cli->cl_grant_extent_tax;
599                         if (grant > 0)
600                                 osc_unreserve_grant(cli, 0, grant);
601
602                         if (ext->oe_urgent)
603                                 list_move_tail(&ext->oe_link,
604                                                &obj->oo_urgent_exts);
605                         else if (ext->oe_nr_pages == ext->oe_mppr) {
606                                 list_move_tail(&ext->oe_link,
607                                                &obj->oo_full_exts);
608                         }
609                 }
610                 osc_object_unlock(obj);
611
612                 osc_io_unplug_async(env, cli, obj);
613         }
614         osc_extent_put(env, ext);
615         RETURN(rc);
616 }
617
618 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
619 {
620         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
621 }
622
623 /**
624  * Find or create an extent which includes @index, core function to manage
625  * extent tree.
626  */
627 static struct osc_extent *osc_extent_find(const struct lu_env *env,
628                                           struct osc_object *obj, pgoff_t index,
629                                           unsigned int *grants)
630 {
631         struct client_obd *cli = osc_cli(obj);
632         struct osc_lock   *olck;
633         struct cl_lock_descr *descr;
634         struct osc_extent *cur;
635         struct osc_extent *ext;
636         struct osc_extent *conflict = NULL;
637         struct osc_extent *found = NULL;
638         pgoff_t    chunk;
639         pgoff_t    max_end;
640         unsigned int max_pages; /* max_pages_per_rpc */
641         unsigned int chunksize;
642         int        ppc_bits; /* pages per chunk bits */
643         pgoff_t    chunk_mask;
644         int        rc;
645         ENTRY;
646
647         cur = osc_extent_alloc(obj);
648         if (cur == NULL)
649                 RETURN(ERR_PTR(-ENOMEM));
650
651         olck = osc_env_io(env)->oi_write_osclock;
652         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
653         LASSERT(olck->ols_state == OLS_GRANTED);
654
655         descr = &olck->ols_cl.cls_lock->cll_descr;
656         LASSERT(descr->cld_mode >= CLM_WRITE);
657
658         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
659                  "chunkbits: %u\n", cli->cl_chunkbits);
660         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
661         chunk_mask = ~((1 << ppc_bits) - 1);
662         chunksize  = 1 << cli->cl_chunkbits;
663         chunk      = index >> ppc_bits;
664
665         /* align end to RPC edge. */
666         max_pages = cli->cl_max_pages_per_rpc;
667         if ((max_pages & ~chunk_mask) != 0) {
668                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
669                        max_pages, cli->cl_chunkbits, chunk_mask);
670                 RETURN(ERR_PTR(-EINVAL));
671         }
672         max_end = index - (index % max_pages) + max_pages - 1;
673         max_end = min_t(pgoff_t, max_end, descr->cld_end);
674
675         /* initialize new extent by parameters so far */
676         cur->oe_max_end = max_end;
677         cur->oe_start   = index & chunk_mask;
678         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
679         if (cur->oe_start < descr->cld_start)
680                 cur->oe_start = descr->cld_start;
681         if (cur->oe_end > max_end)
682                 cur->oe_end = max_end;
683         cur->oe_grants  = 0;
684         cur->oe_mppr    = max_pages;
685         if (olck->ols_dlmlock != NULL) {
686                 LASSERT(olck->ols_hold);
687                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
688                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
689         }
690
691         /* grants has been allocated by caller */
692         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
693                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
694         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
695                  EXTPARA(cur));
696
697 restart:
698         osc_object_lock(obj);
699         ext = osc_extent_search(obj, cur->oe_start);
700         if (ext == NULL)
701                 ext = first_extent(obj);
702         while (ext != NULL) {
703                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
704                 pgoff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
705
706                 LASSERT(sanity_check_nolock(ext) == 0);
707                 if (chunk > ext_chk_end + 1 || chunk < ext_chk_start)
708                         break;
709
710                 /* if covering by different locks, no chance to match */
711                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
712                         EASSERTF(!overlapped(ext, cur), ext,
713                                  EXTSTR"\n", EXTPARA(cur));
714
715                         ext = next_extent(ext);
716                         continue;
717                 }
718
719                 /* discontiguous chunks? */
720                 if (chunk + 1 < ext_chk_start) {
721                         ext = next_extent(ext);
722                         continue;
723                 }
724
725                 /* ok, from now on, ext and cur have these attrs:
726                  * 1. covered by the same lock
727                  * 2. contiguous at chunk level or overlapping. */
728
729                 if (overlapped(ext, cur)) {
730                         /* cur is the minimum unit, so overlapping means
731                          * full contain. */
732                         EASSERTF((ext->oe_start <= cur->oe_start &&
733                                   ext->oe_end >= cur->oe_end),
734                                  ext, EXTSTR"\n", EXTPARA(cur));
735
736                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
737                                 /* for simplicity, we wait for this extent to
738                                  * finish before going forward. */
739                                 conflict = osc_extent_get(ext);
740                                 break;
741                         }
742
743                         found = osc_extent_hold(ext);
744                         break;
745                 }
746
747                 /* non-overlapped extent */
748                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
749                         /* we can't do anything for a non OES_CACHE extent, or
750                          * if there is someone waiting for this extent to be
751                          * flushed, try next one. */
752                         ext = next_extent(ext);
753                         continue;
754                 }
755
756                 /* check if they belong to the same rpc slot before trying to
757                  * merge. the extents are not overlapped and contiguous at
758                  * chunk level to get here. */
759                 if (ext->oe_max_end != max_end) {
760                         /* if they don't belong to the same RPC slot or
761                          * max_pages_per_rpc has ever changed, do not merge. */
762                         ext = next_extent(ext);
763                         continue;
764                 }
765
766                 /* check whether maximum extent size will be hit */
767                 if ((ext_chk_end - ext_chk_start + 1 + 1) << ppc_bits >
768                     cli->cl_max_extent_pages) {
769                         ext = next_extent(ext);
770                         continue;
771                 }
772
773                 /* it's required that an extent must be contiguous at chunk
774                  * level so that we know the whole extent is covered by grant
775                  * (the pages in the extent are NOT required to be contiguous).
776                  * Otherwise, it will be too much difficult to know which
777                  * chunks have grants allocated. */
778
779                 /* try to do front merge - extend ext's start */
780                 if (chunk + 1 == ext_chk_start) {
781                         /* ext must be chunk size aligned */
782                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
783
784                         /* pull ext's start back to cover cur */
785                         ext->oe_start   = cur->oe_start;
786                         ext->oe_grants += chunksize;
787                         LASSERT(*grants >= chunksize);
788                         *grants -= chunksize;
789
790                         found = osc_extent_hold(ext);
791                 } else if (chunk == ext_chk_end + 1) {
792                         /* rear merge */
793                         ext->oe_end     = cur->oe_end;
794                         ext->oe_grants += chunksize;
795                         LASSERT(*grants >= chunksize);
796                         *grants -= chunksize;
797
798                         /* try to merge with the next one because we just fill
799                          * in a gap */
800                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
801                                 /* we can save extent tax from next extent */
802                                 *grants += cli->cl_grant_extent_tax;
803
804                         found = osc_extent_hold(ext);
805                 }
806                 if (found != NULL)
807                         break;
808
809                 ext = next_extent(ext);
810         }
811
812         osc_extent_tree_dump(D_CACHE, obj);
813         if (found != NULL) {
814                 LASSERT(conflict == NULL);
815                 if (!IS_ERR(found)) {
816                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
817                         OSC_EXTENT_DUMP(D_CACHE, found,
818                                         "found caching ext for %lu.\n", index);
819                 }
820         } else if (conflict == NULL) {
821                 /* create a new extent */
822                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
823                 cur->oe_grants = chunksize + cli->cl_grant_extent_tax;
824                 LASSERT(*grants >= cur->oe_grants);
825                 *grants -= cur->oe_grants;
826
827                 cur->oe_state = OES_CACHE;
828                 found = osc_extent_hold(cur);
829                 osc_extent_insert(obj, cur);
830                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
831                                 index, descr->cld_end);
832         }
833         osc_object_unlock(obj);
834
835         if (conflict != NULL) {
836                 LASSERT(found == NULL);
837
838                 /* waiting for IO to finish. Please notice that it's impossible
839                  * to be an OES_TRUNC extent. */
840                 rc = osc_extent_wait(env, conflict, OES_INV);
841                 osc_extent_put(env, conflict);
842                 conflict = NULL;
843                 if (rc < 0)
844                         GOTO(out, found = ERR_PTR(rc));
845
846                 goto restart;
847         }
848         EXIT;
849
850 out:
851         osc_extent_put(env, cur);
852         return found;
853 }
854
855 /**
856  * Called when IO is finished to an extent.
857  */
858 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
859                       int sent, int rc)
860 {
861         struct client_obd *cli = osc_cli(ext->oe_obj);
862         struct osc_async_page *oap;
863         struct osc_async_page *tmp;
864         int nr_pages = ext->oe_nr_pages;
865         int lost_grant = 0;
866         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
867         loff_t last_off = 0;
868         int last_count = -1;
869         ENTRY;
870
871         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
872
873         ext->oe_rc = rc ?: ext->oe_nr_pages;
874         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
875
876         osc_lru_add_batch(cli, &ext->oe_pages);
877         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
878                                      oap_pending_item) {
879                 list_del_init(&oap->oap_rpc_item);
880                 list_del_init(&oap->oap_pending_item);
881                 if (last_off <= oap->oap_obj_off) {
882                         last_off = oap->oap_obj_off;
883                         last_count = oap->oap_count;
884                 }
885
886                 --ext->oe_nr_pages;
887                 osc_ap_completion(env, cli, oap, sent, rc);
888         }
889         EASSERT(ext->oe_nr_pages == 0, ext);
890
891         if (!sent) {
892                 lost_grant = ext->oe_grants;
893         } else if (blocksize < PAGE_SIZE &&
894                    last_count != PAGE_SIZE) {
895                 /* For short writes we shouldn't count parts of pages that
896                  * span a whole chunk on the OST side, or our accounting goes
897                  * wrong.  Should match the code in filter_grant_check. */
898                 int offset = last_off & ~PAGE_MASK;
899                 int count = last_count + (offset & (blocksize - 1));
900                 int end = (offset + last_count) & (blocksize - 1);
901                 if (end)
902                         count += blocksize - end;
903
904                 lost_grant = PAGE_SIZE - count;
905         }
906         if (ext->oe_grants > 0)
907                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
908
909         osc_extent_remove(ext);
910         /* put the refcount for RPC */
911         osc_extent_put(env, ext);
912         RETURN(0);
913 }
914
915 static int extent_wait_cb(struct osc_extent *ext, enum osc_extent_state state)
916 {
917         int ret;
918
919         osc_object_lock(ext->oe_obj);
920         ret = ext->oe_state == state;
921         osc_object_unlock(ext->oe_obj);
922
923         return ret;
924 }
925
926 /**
927  * Wait for the extent's state to become @state.
928  */
929 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
930                            enum osc_extent_state state)
931 {
932         struct osc_object *obj = ext->oe_obj;
933         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
934                                                   LWI_ON_SIGNAL_NOOP, NULL);
935         int rc = 0;
936         ENTRY;
937
938         osc_object_lock(obj);
939         LASSERT(sanity_check_nolock(ext) == 0);
940         /* `Kick' this extent only if the caller is waiting for it to be
941          * written out. */
942         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
943                 if (ext->oe_state == OES_ACTIVE) {
944                         ext->oe_urgent = 1;
945                 } else if (ext->oe_state == OES_CACHE) {
946                         ext->oe_urgent = 1;
947                         osc_extent_hold(ext);
948                         rc = 1;
949                 }
950         }
951         osc_object_unlock(obj);
952         if (rc == 1)
953                 osc_extent_release(env, ext);
954
955         /* wait for the extent until its state becomes @state */
956         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
957         if (rc == -ETIMEDOUT) {
958                 OSC_EXTENT_DUMP(D_ERROR, ext,
959                         "%s: wait ext to %u timedout, recovery in progress?\n",
960                         cli_name(osc_cli(obj)), state);
961
962                 lwi = LWI_INTR(NULL, NULL);
963                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
964                                   &lwi);
965         }
966         if (rc == 0 && ext->oe_rc < 0)
967                 rc = ext->oe_rc;
968         RETURN(rc);
969 }
970
971 /**
972  * Discard pages with index greater than @size. If @ext is overlapped with
973  * @size, then partial truncate happens.
974  */
975 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
976                                 bool partial)
977 {
978         struct lu_env         *env;
979         struct cl_io          *io;
980         struct osc_object     *obj = ext->oe_obj;
981         struct client_obd     *cli = osc_cli(obj);
982         struct osc_async_page *oap;
983         struct osc_async_page *tmp;
984         struct pagevec        *pvec;
985         int                    pages_in_chunk = 0;
986         int                    ppc_bits    = cli->cl_chunkbits -
987                                              PAGE_SHIFT;
988         __u64                  trunc_chunk = trunc_index >> ppc_bits;
989         int                    grants   = 0;
990         int                    nr_pages = 0;
991         int                    rc       = 0;
992         __u16                  refcheck;
993         ENTRY;
994
995         LASSERT(sanity_check(ext) == 0);
996         LASSERT(ext->oe_state == OES_TRUNC);
997         LASSERT(!ext->oe_urgent);
998
999         /* Request new lu_env.
1000          * We can't use that env from osc_cache_truncate_start() because
1001          * it's from lov_io_sub and not fully initialized. */
1002         env = cl_env_get(&refcheck);
1003         if (IS_ERR(env))
1004                 RETURN(PTR_ERR(env));
1005
1006         io  = osc_env_thread_io(env);
1007         io->ci_obj = cl_object_top(osc2cl(obj));
1008         io->ci_ignore_layout = 1;
1009         pvec = &osc_env_info(env)->oti_pagevec;
1010         ll_pagevec_init(pvec, 0);
1011         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
1012         if (rc < 0)
1013                 GOTO(out, rc);
1014
1015         /* discard all pages with index greater than trunc_index */
1016         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
1017                                      oap_pending_item) {
1018                 pgoff_t index = osc_index(oap2osc(oap));
1019                 struct cl_page  *page = oap2cl_page(oap);
1020
1021                 LASSERT(list_empty(&oap->oap_rpc_item));
1022
1023                 /* only discard the pages with their index greater than
1024                  * trunc_index, and ... */
1025                 if (index < trunc_index ||
1026                     (index == trunc_index && partial)) {
1027                         /* accounting how many pages remaining in the chunk
1028                          * so that we can calculate grants correctly. */
1029                         if (index >> ppc_bits == trunc_chunk)
1030                                 ++pages_in_chunk;
1031                         continue;
1032                 }
1033
1034                 list_del_init(&oap->oap_pending_item);
1035
1036                 cl_page_get(page);
1037                 lu_ref_add(&page->cp_reference, "truncate", current);
1038
1039                 if (cl_page_own(env, io, page) == 0) {
1040                         cl_page_discard(env, io, page);
1041                         cl_page_disown(env, io, page);
1042                 } else {
1043                         LASSERT(page->cp_state == CPS_FREEING);
1044                         LASSERT(0);
1045                 }
1046
1047                 lu_ref_del(&page->cp_reference, "truncate", current);
1048                 cl_pagevec_put(env, page, pvec);
1049
1050                 --ext->oe_nr_pages;
1051                 ++nr_pages;
1052         }
1053         pagevec_release(pvec);
1054
1055         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1056                       ext->oe_nr_pages == 0),
1057                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1058
1059         osc_object_lock(obj);
1060         if (ext->oe_nr_pages == 0) {
1061                 LASSERT(pages_in_chunk == 0);
1062                 grants = ext->oe_grants;
1063                 ext->oe_grants = 0;
1064         } else { /* calculate how many grants we can free */
1065                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1066                 pgoff_t last_index;
1067
1068
1069                 /* if there is no pages in this chunk, we can also free grants
1070                  * for the last chunk */
1071                 if (pages_in_chunk == 0) {
1072                         /* if this is the 1st chunk and no pages in this chunk,
1073                          * ext->oe_nr_pages must be zero, so we should be in
1074                          * the other if-clause. */
1075                         LASSERT(trunc_chunk > 0);
1076                         --trunc_chunk;
1077                         ++chunks;
1078                 }
1079
1080                 /* this is what we can free from this extent */
1081                 grants          = chunks << cli->cl_chunkbits;
1082                 ext->oe_grants -= grants;
1083                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1084                 ext->oe_end     = min(last_index, ext->oe_max_end);
1085                 LASSERT(ext->oe_end >= ext->oe_start);
1086                 LASSERT(ext->oe_grants > 0);
1087         }
1088         osc_object_unlock(obj);
1089
1090         if (grants > 0 || nr_pages > 0)
1091                 osc_free_grant(cli, nr_pages, grants, grants);
1092
1093 out:
1094         cl_io_fini(env, io);
1095         cl_env_put(env, &refcheck);
1096         RETURN(rc);
1097 }
1098
1099 /**
1100  * This function is used to make the extent prepared for transfer.
1101  * A race with flusing page - ll_writepage() has to be handled cautiously.
1102  */
1103 static int osc_extent_make_ready(const struct lu_env *env,
1104                                  struct osc_extent *ext)
1105 {
1106         struct osc_async_page *oap;
1107         struct osc_async_page *last = NULL;
1108         struct osc_object *obj = ext->oe_obj;
1109         unsigned int page_count = 0;
1110         int rc;
1111         ENTRY;
1112
1113         /* we're going to grab page lock, so object lock must not be taken. */
1114         LASSERT(sanity_check(ext) == 0);
1115         /* in locking state, any process should not touch this extent. */
1116         EASSERT(ext->oe_state == OES_LOCKING, ext);
1117         EASSERT(ext->oe_owner != NULL, ext);
1118
1119         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1120
1121         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1122                 ++page_count;
1123                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1124                         last = oap;
1125
1126                 /* checking ASYNC_READY is race safe */
1127                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1128                         continue;
1129
1130                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1131                 switch (rc) {
1132                 case 0:
1133                         spin_lock(&oap->oap_lock);
1134                         oap->oap_async_flags |= ASYNC_READY;
1135                         spin_unlock(&oap->oap_lock);
1136                         break;
1137                 case -EALREADY:
1138                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1139                         break;
1140                 default:
1141                         LASSERTF(0, "unknown return code: %d\n", rc);
1142                 }
1143         }
1144
1145         LASSERT(page_count == ext->oe_nr_pages);
1146         LASSERT(last != NULL);
1147         /* the last page is the only one we need to refresh its count by
1148          * the size of file. */
1149         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1150                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1151                 LASSERT(last_oap_count > 0);
1152                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1153                 last->oap_count = last_oap_count;
1154                 spin_lock(&last->oap_lock);
1155                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1156                 spin_unlock(&last->oap_lock);
1157         }
1158
1159         /* for the rest of pages, we don't need to call osf_refresh_count()
1160          * because it's known they are not the last page */
1161         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1162                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1163                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1164                         spin_lock(&oap->oap_lock);
1165                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1166                         spin_unlock(&oap->oap_lock);
1167                 }
1168         }
1169
1170         osc_object_lock(obj);
1171         osc_extent_state_set(ext, OES_RPC);
1172         osc_object_unlock(obj);
1173         /* get a refcount for RPC. */
1174         osc_extent_get(ext);
1175
1176         RETURN(0);
1177 }
1178
1179 /**
1180  * Quick and simple version of osc_extent_find(). This function is frequently
1181  * called to expand the extent for the same IO. To expand the extent, the
1182  * page index must be in the same or next chunk of ext->oe_end.
1183  */
1184 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1185                              unsigned int *grants)
1186 {
1187         struct osc_object *obj = ext->oe_obj;
1188         struct client_obd *cli = osc_cli(obj);
1189         struct osc_extent *next;
1190         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1191         pgoff_t chunk = index >> ppc_bits;
1192         pgoff_t end_chunk;
1193         pgoff_t end_index;
1194         unsigned int chunksize = 1 << cli->cl_chunkbits;
1195         int rc = 0;
1196         ENTRY;
1197
1198         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1199         osc_object_lock(obj);
1200         LASSERT(sanity_check_nolock(ext) == 0);
1201         end_chunk = ext->oe_end >> ppc_bits;
1202         if (chunk > end_chunk + 1)
1203                 GOTO(out, rc = -ERANGE);
1204
1205         if (end_chunk >= chunk)
1206                 GOTO(out, rc = 0);
1207
1208         LASSERT(end_chunk + 1 == chunk);
1209
1210         /* try to expand this extent to cover @index */
1211         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1212
1213         /* don't go over the maximum extent size reported by server */
1214         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1215                 GOTO(out, rc = -ERANGE);
1216
1217         next = next_extent(ext);
1218         if (next != NULL && next->oe_start <= end_index)
1219                 /* complex mode - overlapped with the next extent,
1220                  * this case will be handled by osc_extent_find() */
1221                 GOTO(out, rc = -EAGAIN);
1222
1223         ext->oe_end = end_index;
1224         ext->oe_grants += chunksize;
1225         LASSERT(*grants >= chunksize);
1226         *grants -= chunksize;
1227         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1228                  "overlapped after expanding for %lu.\n", index);
1229         EXIT;
1230
1231 out:
1232         osc_object_unlock(obj);
1233         RETURN(rc);
1234 }
1235
1236 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
1237                                   const char *func, int line)
1238 {
1239         struct osc_extent *ext;
1240         int cnt;
1241
1242         if (!cfs_cdebug_show(mask, DEBUG_SUBSYSTEM))
1243                 return;
1244
1245         CDEBUG(mask, "Dump object %p extents at %s:%d, mppr: %u.\n",
1246                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1247
1248         /* osc_object_lock(obj); */
1249         cnt = 1;
1250         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1251                 OSC_EXTENT_DUMP(mask, ext, "in tree %d.\n", cnt++);
1252
1253         cnt = 1;
1254         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1255                 OSC_EXTENT_DUMP(mask, ext, "hp %d.\n", cnt++);
1256
1257         cnt = 1;
1258         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1259                 OSC_EXTENT_DUMP(mask, ext, "urgent %d.\n", cnt++);
1260
1261         cnt = 1;
1262         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1263                 OSC_EXTENT_DUMP(mask, ext, "reading %d.\n", cnt++);
1264         /* osc_object_unlock(obj); */
1265 }
1266
1267 /* ------------------ osc extent end ------------------ */
1268
1269 static inline int osc_is_ready(struct osc_object *osc)
1270 {
1271         return !list_empty(&osc->oo_ready_item) ||
1272                !list_empty(&osc->oo_hp_ready_item);
1273 }
1274
1275 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1276         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1277                (OSC), osc_is_ready(OSC),                                       \
1278                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1279                list_empty_marker(&(OSC)->oo_ready_item),                       \
1280                atomic_read(&(OSC)->oo_nr_writes),                              \
1281                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1282                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1283                atomic_read(&(OSC)->oo_nr_reads),                               \
1284                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1285                ##args)
1286
1287 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1288                           int cmd)
1289 {
1290         struct osc_page *opg  = oap2osc_page(oap);
1291         struct cl_page  *page = oap2cl_page(oap);
1292         int result;
1293
1294         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1295
1296         ENTRY;
1297         result = cl_page_make_ready(env, page, CRT_WRITE);
1298         if (result == 0)
1299                 opg->ops_submit_time = ktime_get();
1300         RETURN(result);
1301 }
1302
1303 static int osc_refresh_count(const struct lu_env *env,
1304                              struct osc_async_page *oap, int cmd)
1305 {
1306         struct osc_page  *opg = oap2osc_page(oap);
1307         pgoff_t index = osc_index(oap2osc(oap));
1308         struct cl_object *obj;
1309         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1310         int result;
1311         loff_t kms;
1312
1313         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1314         LASSERT(!(cmd & OBD_BRW_READ));
1315         LASSERT(opg != NULL);
1316         obj = opg->ops_cl.cpl_obj;
1317
1318         cl_object_attr_lock(obj);
1319         result = cl_object_attr_get(env, obj, attr);
1320         cl_object_attr_unlock(obj);
1321         if (result < 0)
1322                 return result;
1323         kms = attr->cat_kms;
1324         if (cl_offset(obj, index) >= kms)
1325                 /* catch race with truncate */
1326                 return 0;
1327         else if (cl_offset(obj, index + 1) > kms)
1328                 /* catch sub-page write at end of file */
1329                 return kms % PAGE_SIZE;
1330         else
1331                 return PAGE_SIZE;
1332 }
1333
1334 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1335                           int cmd, int rc)
1336 {
1337         struct osc_page   *opg  = oap2osc_page(oap);
1338         struct cl_page    *page = oap2cl_page(oap);
1339         enum cl_req_type   crt;
1340         int srvlock;
1341
1342         ENTRY;
1343
1344         cmd &= ~OBD_BRW_NOQUOTA;
1345         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1346                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1347         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1348                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1349         LASSERT(opg->ops_transfer_pinned);
1350
1351         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1352         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1353         opg->ops_transfer_pinned = 0;
1354
1355         opg->ops_submit_time = ktime_set(0, 0);
1356         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1357
1358         /* statistic */
1359         if (rc == 0 && srvlock) {
1360                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1361                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1362                 size_t bytes = oap->oap_count;
1363
1364                 if (crt == CRT_READ)
1365                         stats->os_lockless_reads += bytes;
1366                 else
1367                         stats->os_lockless_writes += bytes;
1368         }
1369
1370         /*
1371          * This has to be the last operation with the page, as locks are
1372          * released in cl_page_completion() and nothing except for the
1373          * reference counter protects page from concurrent reclaim.
1374          */
1375         lu_ref_del(&page->cp_reference, "transfer", page);
1376
1377         cl_page_completion(env, page, crt, rc);
1378         cl_page_put(env, page);
1379
1380         RETURN(0);
1381 }
1382
1383 #define OSC_DUMP_GRANT(mask, cli, fmt, args...) do {                    \
1384         struct client_obd *__tmp = (cli);                               \
1385         CDEBUG(mask, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu " \
1386                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1387                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1388                "left: %ld, waiters: %d }" fmt "\n",                     \
1389                cli_name(__tmp),                                         \
1390                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1391                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1392                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1393                __tmp->cl_dirty_grant,                                   \
1394                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1395                atomic_long_read(&__tmp->cl_lru_in_list),                \
1396                atomic_long_read(&__tmp->cl_lru_busy),                   \
1397                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1398 } while (0)
1399
1400 /* caller must hold loi_list_lock */
1401 static void osc_consume_write_grant(struct client_obd *cli,
1402                                     struct brw_page *pga)
1403 {
1404         assert_spin_locked(&cli->cl_loi_list_lock);
1405         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1406         cli->cl_dirty_pages++;
1407         pga->flag |= OBD_BRW_FROM_GRANT;
1408         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1409                PAGE_SIZE, pga, pga->pg);
1410         osc_update_next_shrink(cli);
1411 }
1412
1413 /* the companion to osc_consume_write_grant, called when a brw has completed.
1414  * must be called with the loi lock held. */
1415 static void osc_release_write_grant(struct client_obd *cli,
1416                                     struct brw_page *pga)
1417 {
1418         ENTRY;
1419
1420         assert_spin_locked(&cli->cl_loi_list_lock);
1421         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1422                 EXIT;
1423                 return;
1424         }
1425
1426         pga->flag &= ~OBD_BRW_FROM_GRANT;
1427         atomic_long_dec(&obd_dirty_pages);
1428         cli->cl_dirty_pages--;
1429         if (pga->flag & OBD_BRW_NOCACHE) {
1430                 pga->flag &= ~OBD_BRW_NOCACHE;
1431                 atomic_long_dec(&obd_dirty_transit_pages);
1432                 cli->cl_dirty_transit--;
1433         }
1434         EXIT;
1435 }
1436
1437 /**
1438  * To avoid sleeping with object lock held, it's good for us allocate enough
1439  * grants before entering into critical section.
1440  *
1441  * client_obd_list_lock held by caller
1442  */
1443 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1444 {
1445         int rc = -EDQUOT;
1446
1447         if (cli->cl_avail_grant >= bytes) {
1448                 cli->cl_avail_grant    -= bytes;
1449                 cli->cl_reserved_grant += bytes;
1450                 rc = 0;
1451         }
1452         return rc;
1453 }
1454
1455 static void __osc_unreserve_grant(struct client_obd *cli,
1456                                   unsigned int reserved, unsigned int unused)
1457 {
1458         /* it's quite normal for us to get more grant than reserved.
1459          * Thinking about a case that two extents merged by adding a new
1460          * chunk, we can save one extent tax. If extent tax is greater than
1461          * one chunk, we can save more grant by adding a new chunk */
1462         cli->cl_reserved_grant -= reserved;
1463         if (unused > reserved) {
1464                 cli->cl_avail_grant += reserved;
1465                 cli->cl_lost_grant  += unused - reserved;
1466                 cli->cl_dirty_grant -= unused - reserved;
1467         } else {
1468                 cli->cl_avail_grant += unused;
1469                 cli->cl_dirty_grant += reserved - unused;
1470         }
1471 }
1472
1473 static void osc_unreserve_grant(struct client_obd *cli,
1474                                 unsigned int reserved, unsigned int unused)
1475 {
1476         spin_lock(&cli->cl_loi_list_lock);
1477         __osc_unreserve_grant(cli, reserved, unused);
1478         if (unused > 0)
1479                 osc_wake_cache_waiters(cli);
1480         spin_unlock(&cli->cl_loi_list_lock);
1481 }
1482
1483 /**
1484  * Free grant after IO is finished or canceled.
1485  *
1486  * @lost_grant is used to remember how many grants we have allocated but not
1487  * used, we should return these grants to OST. There're two cases where grants
1488  * can be lost:
1489  * 1. truncate;
1490  * 2. blocksize at OST is less than PAGE_SIZE and a partial page was
1491  *    written. In this case OST may use less chunks to serve this partial
1492  *    write. OSTs don't actually know the page size on the client side. so
1493  *    clients have to calculate lost grant by the blocksize on the OST.
1494  *    See filter_grant_check() for details.
1495  */
1496 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1497                            unsigned int lost_grant, unsigned int dirty_grant)
1498 {
1499         unsigned long grant;
1500
1501         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1502
1503         spin_lock(&cli->cl_loi_list_lock);
1504         atomic_long_sub(nr_pages, &obd_dirty_pages);
1505         cli->cl_dirty_pages -= nr_pages;
1506         cli->cl_lost_grant += lost_grant;
1507         cli->cl_dirty_grant -= dirty_grant;
1508         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1509                 /* borrow some grant from truncate to avoid the case that
1510                  * truncate uses up all avail grant */
1511                 cli->cl_lost_grant -= grant;
1512                 cli->cl_avail_grant += grant;
1513         }
1514         osc_wake_cache_waiters(cli);
1515         spin_unlock(&cli->cl_loi_list_lock);
1516         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1517                lost_grant, cli->cl_lost_grant,
1518                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1519                cli->cl_dirty_grant);
1520 }
1521
1522 /**
1523  * The companion to osc_enter_cache(), called when @oap is no longer part of
1524  * the dirty accounting due to error.
1525  */
1526 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1527 {
1528         spin_lock(&cli->cl_loi_list_lock);
1529         osc_release_write_grant(cli, &oap->oap_brw_page);
1530         spin_unlock(&cli->cl_loi_list_lock);
1531 }
1532
1533 /**
1534  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1535  * is available.
1536  */
1537 static int osc_enter_cache_try(struct client_obd *cli,
1538                                struct osc_async_page *oap,
1539                                int bytes, int transient)
1540 {
1541         int rc;
1542
1543         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1544
1545         rc = osc_reserve_grant(cli, bytes);
1546         if (rc < 0)
1547                 return 0;
1548
1549         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages) {
1550                 if (atomic_long_add_return(1, &obd_dirty_pages) <=
1551                     obd_max_dirty_pages) {
1552                         osc_consume_write_grant(cli, &oap->oap_brw_page);
1553                         if (transient) {
1554                                 cli->cl_dirty_transit++;
1555                                 atomic_long_inc(&obd_dirty_transit_pages);
1556                                 oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1557                         }
1558                         rc = 1;
1559                         goto out;
1560                 } else
1561                         atomic_long_dec(&obd_dirty_pages);
1562         }
1563         __osc_unreserve_grant(cli, bytes, bytes);
1564
1565 out:
1566         return rc;
1567 }
1568
1569 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1570 {
1571         int rc;
1572         spin_lock(&cli->cl_loi_list_lock);
1573         rc = list_empty(&ocw->ocw_entry);
1574         spin_unlock(&cli->cl_loi_list_lock);
1575         return rc;
1576 }
1577
1578 /**
1579  * The main entry to reserve dirty page accounting. Usually the grant reserved
1580  * in this function will be freed in bulk in osc_free_grant() unless it fails
1581  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1582  *
1583  * The process will be put into sleep if it's already run out of grant.
1584  */
1585 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1586                            struct osc_async_page *oap, int bytes)
1587 {
1588         struct osc_object       *osc = oap->oap_obj;
1589         struct lov_oinfo        *loi = osc->oo_oinfo;
1590         struct osc_cache_waiter  ocw;
1591         struct l_wait_info       lwi;
1592         int                      rc = -EDQUOT;
1593         ENTRY;
1594
1595         lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(AT_OFF ? obd_timeout : at_max),
1596                                NULL, LWI_ON_SIGNAL_NOOP, NULL);
1597
1598         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1599
1600         spin_lock(&cli->cl_loi_list_lock);
1601
1602         /* force the caller to try sync io.  this can jump the list
1603          * of queued writes and create a discontiguous rpc stream */
1604         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1605             cli->cl_dirty_max_pages == 0 ||
1606             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1607                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1608                 GOTO(out, rc = -EDQUOT);
1609         }
1610
1611         /* Hopefully normal case - cache space and write credits available */
1612         if (list_empty(&cli->cl_cache_waiters) &&
1613             osc_enter_cache_try(cli, oap, bytes, 0)) {
1614                 OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1615                 GOTO(out, rc = 0);
1616         }
1617
1618         /* We can get here for two reasons: too many dirty pages in cache, or
1619          * run out of grants. In both cases we should write dirty pages out.
1620          * Adding a cache waiter will trigger urgent write-out no matter what
1621          * RPC size will be.
1622          * The exiting condition is no avail grants and no dirty pages caching,
1623          * that really means there is no space on the OST. */
1624         init_waitqueue_head(&ocw.ocw_waitq);
1625         ocw.ocw_oap   = oap;
1626         ocw.ocw_grant = bytes;
1627         while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
1628                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1629                 ocw.ocw_rc = 0;
1630                 spin_unlock(&cli->cl_loi_list_lock);
1631
1632                 osc_io_unplug_async(env, cli, NULL);
1633
1634                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1635                        cli_name(cli), &ocw, oap);
1636
1637                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1638
1639                 spin_lock(&cli->cl_loi_list_lock);
1640
1641                 if (rc < 0) {
1642                         /* l_wait_event is interrupted by signal or timed out */
1643                         list_del_init(&ocw.ocw_entry);
1644                         break;
1645                 }
1646                 LASSERT(list_empty(&ocw.ocw_entry));
1647                 rc = ocw.ocw_rc;
1648
1649                 if (rc != -EDQUOT)
1650                         break;
1651                 if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1652                         rc = 0;
1653                         break;
1654                 }
1655         }
1656
1657         switch (rc) {
1658         case 0:
1659                 OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space\n");
1660                 break;
1661         case -ETIMEDOUT:
1662                 OSC_DUMP_GRANT(D_CACHE, cli,
1663                                "timeout, fall back to sync i/o\n");
1664                 osc_extent_tree_dump(D_CACHE, osc);
1665                 /* fall back to synchronous I/O */
1666                 rc = -EDQUOT;
1667                 break;
1668         case -EINTR:
1669                 /* Ensures restartability - LU-3581 */
1670                 OSC_DUMP_GRANT(D_CACHE, cli, "interrupted\n");
1671                 rc = -ERESTARTSYS;
1672                 break;
1673         case -EDQUOT:
1674                 OSC_DUMP_GRANT(D_CACHE, cli,
1675                                "no grant space, fall back to sync i/o\n");
1676                 break;
1677         default:
1678                 CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived "
1679                        "due to %d, fall back to sync i/o\n",
1680                        cli_name(cli), &ocw, rc);
1681                 break;
1682         }
1683         EXIT;
1684 out:
1685         spin_unlock(&cli->cl_loi_list_lock);
1686         RETURN(rc);
1687 }
1688
1689 /* caller must hold loi_list_lock */
1690 void osc_wake_cache_waiters(struct client_obd *cli)
1691 {
1692         struct list_head *l, *tmp;
1693         struct osc_cache_waiter *ocw;
1694
1695         ENTRY;
1696         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1697                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1698
1699                 ocw->ocw_rc = -EDQUOT;
1700
1701                 if (osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1702                         ocw->ocw_rc = 0;
1703
1704                 if (ocw->ocw_rc == 0 ||
1705                     !(cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0)) {
1706                         list_del_init(&ocw->ocw_entry);
1707                         CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant "
1708                                "%ld, %d\n", ocw, ocw->ocw_oap,
1709                                cli->cl_avail_grant, ocw->ocw_rc);
1710
1711                         wake_up(&ocw->ocw_waitq);
1712                 }
1713         }
1714
1715         EXIT;
1716 }
1717 EXPORT_SYMBOL(osc_wake_cache_waiters);
1718
1719 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1720 {
1721         int hprpc = !!list_empty(&osc->oo_hp_exts);
1722         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1723 }
1724
1725 /* This maintains the lists of pending pages to read/write for a given object
1726  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1727  * to quickly find objects that are ready to send an RPC. */
1728 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1729                          int cmd)
1730 {
1731         int invalid_import = 0;
1732         ENTRY;
1733
1734         /* if we have an invalid import we want to drain the queued pages
1735          * by forcing them through rpcs that immediately fail and complete
1736          * the pages.  recovery relies on this to empty the queued pages
1737          * before canceling the locks and evicting down the llite pages */
1738         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1739                 invalid_import = 1;
1740
1741         if (cmd & OBD_BRW_WRITE) {
1742                 if (atomic_read(&osc->oo_nr_writes) == 0)
1743                         RETURN(0);
1744                 if (invalid_import) {
1745                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1746                         RETURN(1);
1747                 }
1748                 if (!list_empty(&osc->oo_hp_exts)) {
1749                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1750                         RETURN(1);
1751                 }
1752                 if (!list_empty(&osc->oo_urgent_exts)) {
1753                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1754                         RETURN(1);
1755                 }
1756                 /* trigger a write rpc stream as long as there are dirtiers
1757                  * waiting for space.  as they're waiting, they're not going to
1758                  * create more pages to coalesce with what's waiting.. */
1759                 if (!list_empty(&cli->cl_cache_waiters)) {
1760                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1761                         RETURN(1);
1762                 }
1763                 if (!list_empty(&osc->oo_full_exts)) {
1764                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1765                         RETURN(1);
1766                 }
1767         } else {
1768                 if (atomic_read(&osc->oo_nr_reads) == 0)
1769                         RETURN(0);
1770                 if (invalid_import) {
1771                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1772                         RETURN(1);
1773                 }
1774                 /* all read are urgent. */
1775                 if (!list_empty(&osc->oo_reading_exts))
1776                         RETURN(1);
1777         }
1778
1779         RETURN(0);
1780 }
1781
1782 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1783 {
1784         struct client_obd *cli = osc_cli(obj);
1785         if (cmd & OBD_BRW_WRITE) {
1786                 atomic_add(delta, &obj->oo_nr_writes);
1787                 atomic_add(delta, &cli->cl_pending_w_pages);
1788                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1789         } else {
1790                 atomic_add(delta, &obj->oo_nr_reads);
1791                 atomic_add(delta, &cli->cl_pending_r_pages);
1792                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1793         }
1794         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1795 }
1796
1797 static int osc_makes_hprpc(struct osc_object *obj)
1798 {
1799         return !list_empty(&obj->oo_hp_exts);
1800 }
1801
1802 static void on_list(struct list_head *item, struct list_head *list,
1803                     int should_be_on)
1804 {
1805         if (list_empty(item) && should_be_on)
1806                 list_add_tail(item, list);
1807         else if (!list_empty(item) && !should_be_on)
1808                 list_del_init(item);
1809 }
1810
1811 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1812  * can find pages to build into rpcs quickly */
1813 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1814 {
1815         if (osc_makes_hprpc(osc)) {
1816                 /* HP rpc */
1817                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1818                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1819         } else {
1820                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1821                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1822                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1823                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1824         }
1825
1826         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1827                 atomic_read(&osc->oo_nr_writes) > 0);
1828
1829         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1830                 atomic_read(&osc->oo_nr_reads) > 0);
1831
1832         return osc_is_ready(osc);
1833 }
1834
1835 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1836 {
1837         int is_ready;
1838
1839         spin_lock(&cli->cl_loi_list_lock);
1840         is_ready = __osc_list_maint(cli, osc);
1841         spin_unlock(&cli->cl_loi_list_lock);
1842
1843         return is_ready;
1844 }
1845
1846 /* this is trying to propogate async writeback errors back up to the
1847  * application.  As an async write fails we record the error code for later if
1848  * the app does an fsync.  As long as errors persist we force future rpcs to be
1849  * sync so that the app can get a sync error and break the cycle of queueing
1850  * pages for which writeback will fail. */
1851 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1852                            int rc)
1853 {
1854         if (rc) {
1855                 if (!ar->ar_rc)
1856                         ar->ar_rc = rc;
1857
1858                 ar->ar_force_sync = 1;
1859                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1860                 return;
1861
1862         }
1863
1864         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1865                 ar->ar_force_sync = 0;
1866 }
1867
1868 /* this must be called holding the loi list lock to give coverage to exit_cache,
1869  * async_flag maintenance, and oap_request */
1870 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1871                               struct osc_async_page *oap, int sent, int rc)
1872 {
1873         struct osc_object *osc = oap->oap_obj;
1874         struct lov_oinfo  *loi = osc->oo_oinfo;
1875         __u64 xid = 0;
1876
1877         ENTRY;
1878         if (oap->oap_request != NULL) {
1879                 xid = ptlrpc_req_xid(oap->oap_request);
1880                 ptlrpc_req_finished(oap->oap_request);
1881                 oap->oap_request = NULL;
1882         }
1883
1884         /* As the transfer for this page is being done, clear the flags */
1885         spin_lock(&oap->oap_lock);
1886         oap->oap_async_flags = 0;
1887         spin_unlock(&oap->oap_lock);
1888         oap->oap_interrupted = 0;
1889
1890         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1891                 spin_lock(&cli->cl_loi_list_lock);
1892                 osc_process_ar(&cli->cl_ar, xid, rc);
1893                 osc_process_ar(&loi->loi_ar, xid, rc);
1894                 spin_unlock(&cli->cl_loi_list_lock);
1895         }
1896
1897         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1898         if (rc)
1899                 CERROR("completion on oap %p obj %p returns %d.\n",
1900                        oap, osc, rc);
1901
1902         EXIT;
1903 }
1904
1905 struct extent_rpc_data {
1906         struct list_head        *erd_rpc_list;
1907         unsigned int            erd_page_count;
1908         unsigned int            erd_max_pages;
1909         unsigned int            erd_max_chunks;
1910         unsigned int            erd_max_extents;
1911 };
1912
1913 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1914 {
1915         struct client_obd *cli = osc_cli(ext->oe_obj);
1916         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1917
1918         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1919 }
1920
1921 /**
1922  * Try to add extent to one RPC. We need to think about the following things:
1923  * - # of pages must not be over max_pages_per_rpc
1924  * - extent must be compatible with previous ones
1925  */
1926 static int try_to_add_extent_for_io(struct client_obd *cli,
1927                                     struct osc_extent *ext,
1928                                     struct extent_rpc_data *data)
1929 {
1930         struct osc_extent *tmp;
1931         unsigned int chunk_count;
1932         struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
1933                                                       struct osc_async_page,
1934                                                       oap_pending_item);
1935         ENTRY;
1936
1937         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1938                 ext);
1939         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1940
1941         if (data->erd_max_extents == 0)
1942                 RETURN(0);
1943
1944         chunk_count = osc_extent_chunks(ext);
1945         EASSERTF(data->erd_page_count != 0 ||
1946                  chunk_count <= data->erd_max_chunks, ext,
1947                  "The first extent to be fit in a RPC contains %u chunks, "
1948                  "which is over the limit %u.\n", chunk_count,
1949                  data->erd_max_chunks);
1950         if (chunk_count > data->erd_max_chunks)
1951                 RETURN(0);
1952
1953         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1954         EASSERTF(data->erd_page_count != 0 ||
1955                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1956                 "The first extent to be fit in a RPC contains %u pages, "
1957                 "which is over the limit %u.\n", ext->oe_nr_pages,
1958                 data->erd_max_pages);
1959         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1960                 RETURN(0);
1961
1962         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1963                 struct osc_async_page *oap2;
1964                 oap2 = list_first_entry(&tmp->oe_pages, struct osc_async_page,
1965                                         oap_pending_item);
1966                 EASSERT(tmp->oe_owner == current, tmp);
1967 #if 0
1968                 if (overlapped(tmp, ext)) {
1969                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1970                         EASSERT(0, ext);
1971                 }
1972 #endif
1973                 if (oap2cl_page(oap)->cp_type != oap2cl_page(oap2)->cp_type) {
1974                         CDEBUG(D_CACHE, "Do not permit different types of IO "
1975                                "in one RPC\n");
1976                         RETURN(0);
1977                 }
1978
1979                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1980                     !tmp->oe_grants != !ext->oe_grants ||
1981                     tmp->oe_ndelay != ext->oe_ndelay ||
1982                     tmp->oe_no_merge || ext->oe_no_merge)
1983                         RETURN(0);
1984
1985                 /* remove break for strict check */
1986                 break;
1987         }
1988
1989         data->erd_max_extents--;
1990         data->erd_max_chunks -= chunk_count;
1991         data->erd_page_count += ext->oe_nr_pages;
1992         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1993         ext->oe_owner = current;
1994         RETURN(1);
1995 }
1996
1997 /**
1998  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1999  * get_write_extent() takes all appropriate extents in atomic.
2000  *
2001  * The following policy is used to collect extents for IO:
2002  * 1. Add as many HP extents as possible;
2003  * 2. Add the first urgent extent in urgent extent list and take it out of
2004  *    urgent list;
2005  * 3. Add subsequent extents of this urgent extent;
2006  * 4. If urgent list is not empty, goto 2;
2007  * 5. Traverse the extent tree from the 1st extent;
2008  * 6. Above steps exit if there is no space in this RPC.
2009  */
2010 static unsigned int get_write_extents(struct osc_object *obj,
2011                                       struct list_head *rpclist)
2012 {
2013         struct client_obd *cli = osc_cli(obj);
2014         struct osc_extent *ext;
2015         struct extent_rpc_data data = {
2016                 .erd_rpc_list   = rpclist,
2017                 .erd_page_count = 0,
2018                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2019                 .erd_max_chunks = osc_max_write_chunks(cli),
2020                 .erd_max_extents = 256,
2021         };
2022
2023         LASSERT(osc_object_is_locked(obj));
2024         while (!list_empty(&obj->oo_hp_exts)) {
2025                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
2026                                  oe_link);
2027                 LASSERT(ext->oe_state == OES_CACHE);
2028                 if (!try_to_add_extent_for_io(cli, ext, &data))
2029                         return data.erd_page_count;
2030                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2031         }
2032         if (data.erd_page_count == data.erd_max_pages)
2033                 return data.erd_page_count;
2034
2035         while (!list_empty(&obj->oo_urgent_exts)) {
2036                 ext = list_entry(obj->oo_urgent_exts.next,
2037                                  struct osc_extent, oe_link);
2038                 if (!try_to_add_extent_for_io(cli, ext, &data))
2039                         return data.erd_page_count;
2040         }
2041         if (data.erd_page_count == data.erd_max_pages)
2042                 return data.erd_page_count;
2043
2044         /* One key difference between full extents and other extents: full
2045          * extents can usually only be added if the rpclist was empty, so if we
2046          * can't add one, we continue on to trying to add normal extents.  This
2047          * is so we don't miss adding extra extents to an RPC containing high
2048          * priority or urgent extents. */
2049         while (!list_empty(&obj->oo_full_exts)) {
2050                 ext = list_entry(obj->oo_full_exts.next,
2051                                  struct osc_extent, oe_link);
2052                 if (!try_to_add_extent_for_io(cli, ext, &data))
2053                         break;
2054         }
2055         if (data.erd_page_count == data.erd_max_pages)
2056                 return data.erd_page_count;
2057
2058         ext = first_extent(obj);
2059         while (ext != NULL) {
2060                 if ((ext->oe_state != OES_CACHE) ||
2061                     /* this extent may be already in current rpclist */
2062                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
2063                         ext = next_extent(ext);
2064                         continue;
2065                 }
2066
2067                 if (!try_to_add_extent_for_io(cli, ext, &data))
2068                         return data.erd_page_count;
2069
2070                 ext = next_extent(ext);
2071         }
2072         return data.erd_page_count;
2073 }
2074
2075 static int
2076 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
2077                    struct osc_object *osc)
2078 __must_hold(osc)
2079 {
2080         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
2081         struct osc_extent *ext;
2082         struct osc_extent *tmp;
2083         struct osc_extent *first = NULL;
2084         unsigned int page_count = 0;
2085         int srvlock = 0;
2086         int rc = 0;
2087         ENTRY;
2088
2089         LASSERT(osc_object_is_locked(osc));
2090
2091         page_count = get_write_extents(osc, &rpclist);
2092         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
2093
2094         if (list_empty(&rpclist))
2095                 RETURN(0);
2096
2097         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2098
2099         list_for_each_entry(ext, &rpclist, oe_link) {
2100                 LASSERT(ext->oe_state == OES_CACHE ||
2101                         ext->oe_state == OES_LOCK_DONE);
2102                 if (ext->oe_state == OES_CACHE)
2103                         osc_extent_state_set(ext, OES_LOCKING);
2104                 else
2105                         osc_extent_state_set(ext, OES_RPC);
2106         }
2107
2108         /* we're going to grab page lock, so release object lock because
2109          * lock order is page lock -> object lock. */
2110         osc_object_unlock(osc);
2111
2112         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2113                 if (ext->oe_state == OES_LOCKING) {
2114                         rc = osc_extent_make_ready(env, ext);
2115                         if (unlikely(rc < 0)) {
2116                                 list_del_init(&ext->oe_link);
2117                                 osc_extent_finish(env, ext, 0, rc);
2118                                 continue;
2119                         }
2120                 }
2121                 if (first == NULL) {
2122                         first = ext;
2123                         srvlock = ext->oe_srvlock;
2124                 } else {
2125                         LASSERT(srvlock == ext->oe_srvlock);
2126                 }
2127         }
2128
2129         if (!list_empty(&rpclist)) {
2130                 LASSERT(page_count > 0);
2131                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2132                 LASSERT(list_empty(&rpclist));
2133         }
2134
2135         osc_object_lock(osc);
2136         RETURN(rc);
2137 }
2138
2139 /**
2140  * prepare pages for ASYNC io and put pages in send queue.
2141  *
2142  * \param cmd OBD_BRW_* macroses
2143  * \param lop pending pages
2144  *
2145  * \return zero if no page added to send queue.
2146  * \return 1 if pages successfully added to send queue.
2147  * \return negative on errors.
2148  */
2149 static int
2150 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2151                   struct osc_object *osc)
2152 __must_hold(osc)
2153 {
2154         struct osc_extent *ext;
2155         struct osc_extent *next;
2156         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2157         struct extent_rpc_data data = {
2158                 .erd_rpc_list   = &rpclist,
2159                 .erd_page_count = 0,
2160                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2161                 .erd_max_chunks = UINT_MAX,
2162                 .erd_max_extents = UINT_MAX,
2163         };
2164         int rc = 0;
2165         ENTRY;
2166
2167         LASSERT(osc_object_is_locked(osc));
2168         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2169                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2170                 if (!try_to_add_extent_for_io(cli, ext, &data))
2171                         break;
2172                 osc_extent_state_set(ext, OES_RPC);
2173                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2174         }
2175         LASSERT(data.erd_page_count <= data.erd_max_pages);
2176
2177         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2178
2179         if (!list_empty(&rpclist)) {
2180                 osc_object_unlock(osc);
2181
2182                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2183                 LASSERT(list_empty(&rpclist));
2184
2185                 osc_object_lock(osc);
2186         }
2187         RETURN(rc);
2188 }
2189
2190 #define list_to_obj(list, item) ({                                            \
2191         struct list_head *__tmp = (list)->next;                               \
2192         list_del_init(__tmp);                                         \
2193         list_entry(__tmp, struct osc_object, oo_##item);                      \
2194 })
2195
2196 /* This is called by osc_check_rpcs() to find which objects have pages that
2197  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2198 static struct osc_object *osc_next_obj(struct client_obd *cli)
2199 {
2200         ENTRY;
2201
2202         /* First return objects that have blocked locks so that they
2203          * will be flushed quickly and other clients can get the lock,
2204          * then objects which have pages ready to be stuffed into RPCs */
2205         if (!list_empty(&cli->cl_loi_hp_ready_list))
2206                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2207         if (!list_empty(&cli->cl_loi_ready_list))
2208                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2209
2210         /* then if we have cache waiters, return all objects with queued
2211          * writes.  This is especially important when many small files
2212          * have filled up the cache and not been fired into rpcs because
2213          * they don't pass the nr_pending/object threshhold */
2214         if (!list_empty(&cli->cl_cache_waiters) &&
2215             !list_empty(&cli->cl_loi_write_list))
2216                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2217
2218         /* then return all queued objects when we have an invalid import
2219          * so that they get flushed */
2220         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2221                 if (!list_empty(&cli->cl_loi_write_list))
2222                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2223                                            write_item));
2224                 if (!list_empty(&cli->cl_loi_read_list))
2225                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2226                                            read_item));
2227         }
2228         RETURN(NULL);
2229 }
2230
2231 /* called with the loi list lock held */
2232 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2233 __must_hold(&cli->cl_loi_list_lock)
2234 {
2235         struct osc_object *osc;
2236         int rc = 0;
2237         ENTRY;
2238
2239         while ((osc = osc_next_obj(cli)) != NULL) {
2240                 struct cl_object *obj = osc2cl(osc);
2241                 struct lu_ref_link link;
2242
2243                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2244
2245                 if (osc_max_rpc_in_flight(cli, osc)) {
2246                         __osc_list_maint(cli, osc);
2247                         break;
2248                 }
2249
2250                 cl_object_get(obj);
2251                 spin_unlock(&cli->cl_loi_list_lock);
2252                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2253
2254                 /* attempt some read/write balancing by alternating between
2255                  * reads and writes in an object.  The makes_rpc checks here
2256                  * would be redundant if we were getting read/write work items
2257                  * instead of objects.  we don't want send_oap_rpc to drain a
2258                  * partial read pending queue when we're given this object to
2259                  * do io on writes while there are cache waiters */
2260                 osc_object_lock(osc);
2261                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2262                         rc = osc_send_write_rpc(env, cli, osc);
2263                         if (rc < 0) {
2264                                 CERROR("Write request failed with %d\n", rc);
2265
2266                                 /* osc_send_write_rpc failed, mostly because of
2267                                  * memory pressure.
2268                                  *
2269                                  * It can't break here, because if:
2270                                  *  - a page was submitted by osc_io_submit, so
2271                                  *    page locked;
2272                                  *  - no request in flight
2273                                  *  - no subsequent request
2274                                  * The system will be in live-lock state,
2275                                  * because there is no chance to call
2276                                  * osc_io_unplug() and osc_check_rpcs() any
2277                                  * more. pdflush can't help in this case,
2278                                  * because it might be blocked at grabbing
2279                                  * the page lock as we mentioned.
2280                                  *
2281                                  * Anyway, continue to drain pages. */
2282                                 /* break; */
2283                         }
2284                 }
2285                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2286                         rc = osc_send_read_rpc(env, cli, osc);
2287                         if (rc < 0)
2288                                 CERROR("Read request failed with %d\n", rc);
2289                 }
2290                 osc_object_unlock(osc);
2291
2292                 osc_list_maint(cli, osc);
2293                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2294                 cl_object_put(env, obj);
2295
2296                 spin_lock(&cli->cl_loi_list_lock);
2297         }
2298 }
2299
2300 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2301                    struct osc_object *osc, int async)
2302 {
2303         int rc = 0;
2304
2305         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2306                 return 0;
2307
2308         if (!async) {
2309                 spin_lock(&cli->cl_loi_list_lock);
2310                 osc_check_rpcs(env, cli);
2311                 spin_unlock(&cli->cl_loi_list_lock);
2312         } else {
2313                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2314                 LASSERT(cli->cl_writeback_work != NULL);
2315                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2316         }
2317         return rc;
2318 }
2319 EXPORT_SYMBOL(osc_io_unplug0);
2320
2321 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2322                         struct page *page, loff_t offset)
2323 {
2324         struct obd_export     *exp = osc_export(osc);
2325         struct osc_async_page *oap = &ops->ops_oap;
2326         ENTRY;
2327
2328         if (!page)
2329                 return cfs_size_round(sizeof(*oap));
2330
2331         oap->oap_magic = OAP_MAGIC;
2332         oap->oap_cli = &exp->exp_obd->u.cli;
2333         oap->oap_obj = osc;
2334
2335         oap->oap_page = page;
2336         oap->oap_obj_off = offset;
2337         LASSERT(!(offset & ~PAGE_MASK));
2338
2339         INIT_LIST_HEAD(&oap->oap_pending_item);
2340         INIT_LIST_HEAD(&oap->oap_rpc_item);
2341
2342         spin_lock_init(&oap->oap_lock);
2343         CDEBUG(D_INFO, "oap %p page %p obj off %llu\n",
2344                oap, page, oap->oap_obj_off);
2345         RETURN(0);
2346 }
2347 EXPORT_SYMBOL(osc_prep_async_page);
2348
2349 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2350                        struct osc_page *ops)
2351 {
2352         struct osc_io *oio = osc_env_io(env);
2353         struct osc_extent     *ext = NULL;
2354         struct osc_async_page *oap = &ops->ops_oap;
2355         struct client_obd     *cli = oap->oap_cli;
2356         struct osc_object     *osc = oap->oap_obj;
2357         pgoff_t index;
2358         unsigned int tmp;
2359         unsigned int grants = 0;
2360         u32    brw_flags = OBD_BRW_ASYNC;
2361         int    cmd = OBD_BRW_WRITE;
2362         int    need_release = 0;
2363         int    rc = 0;
2364         ENTRY;
2365
2366         if (oap->oap_magic != OAP_MAGIC)
2367                 RETURN(-EINVAL);
2368
2369         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2370                 RETURN(-EIO);
2371
2372         if (!list_empty(&oap->oap_pending_item) ||
2373             !list_empty(&oap->oap_rpc_item))
2374                 RETURN(-EBUSY);
2375
2376         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2377         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2378         if (oio->oi_cap_sys_resource) {
2379                 brw_flags |= OBD_BRW_NOQUOTA;
2380                 cmd |= OBD_BRW_NOQUOTA;
2381         }
2382
2383         /* check if the file's owner/group is over quota */
2384         if (!(cmd & OBD_BRW_NOQUOTA)) {
2385                 struct cl_object *obj;
2386                 struct cl_attr   *attr;
2387                 unsigned int qid[LL_MAXQUOTAS];
2388
2389                 obj = cl_object_top(&osc->oo_cl);
2390                 attr = &osc_env_info(env)->oti_attr;
2391
2392                 cl_object_attr_lock(obj);
2393                 rc = cl_object_attr_get(env, obj, attr);
2394                 cl_object_attr_unlock(obj);
2395
2396                 qid[USRQUOTA] = attr->cat_uid;
2397                 qid[GRPQUOTA] = attr->cat_gid;
2398                 qid[PRJQUOTA] = attr->cat_projid;
2399                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2400                         rc = -EDQUOT;
2401                 if (rc)
2402                         RETURN(rc);
2403         }
2404
2405         oap->oap_cmd = cmd;
2406         oap->oap_page_off = ops->ops_from;
2407         oap->oap_count = ops->ops_to - ops->ops_from;
2408         /* No need to hold a lock here,
2409          * since this page is not in any list yet. */
2410         oap->oap_async_flags = 0;
2411         oap->oap_brw_flags = brw_flags;
2412
2413         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2414                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2415
2416         index = osc_index(oap2osc(oap));
2417
2418         /* Add this page into extent by the following steps:
2419          * 1. if there exists an active extent for this IO, mostly this page
2420          *    can be added to the active extent and sometimes we need to
2421          *    expand extent to accomodate this page;
2422          * 2. otherwise, a new extent will be allocated. */
2423
2424         ext = oio->oi_active;
2425         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2426                 /* one chunk plus extent overhead must be enough to write this
2427                  * page */
2428                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2429                 if (ext->oe_end >= index)
2430                         grants = 0;
2431
2432                 /* it doesn't need any grant to dirty this page */
2433                 spin_lock(&cli->cl_loi_list_lock);
2434                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2435                 spin_unlock(&cli->cl_loi_list_lock);
2436                 if (rc == 0) { /* try failed */
2437                         grants = 0;
2438                         need_release = 1;
2439                 } else if (ext->oe_end < index) {
2440                         tmp = grants;
2441                         /* try to expand this extent */
2442                         rc = osc_extent_expand(ext, index, &tmp);
2443                         if (rc < 0) {
2444                                 need_release = 1;
2445                                 /* don't free reserved grant */
2446                         } else {
2447                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2448                                                 "expanded for %lu.\n", index);
2449                                 osc_unreserve_grant(cli, grants, tmp);
2450                                 grants = 0;
2451                         }
2452                 }
2453                 rc = 0;
2454         } else if (ext != NULL) {
2455                 /* index is located outside of active extent */
2456                 need_release = 1;
2457         }
2458         if (need_release) {
2459                 osc_extent_release(env, ext);
2460                 oio->oi_active = NULL;
2461                 ext = NULL;
2462         }
2463
2464         if (ext == NULL) {
2465                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2466
2467                 /* try to find new extent to cover this page */
2468                 LASSERT(oio->oi_active == NULL);
2469                 /* we may have allocated grant for this page if we failed
2470                  * to expand the previous active extent. */
2471                 LASSERT(ergo(grants > 0, grants >= tmp));
2472
2473                 rc = 0;
2474                 if (grants == 0) {
2475                         /* we haven't allocated grant for this page. */
2476                         rc = osc_enter_cache(env, cli, oap, tmp);
2477                         if (rc == 0)
2478                                 grants = tmp;
2479                 }
2480
2481                 tmp = grants;
2482                 if (rc == 0) {
2483                         ext = osc_extent_find(env, osc, index, &tmp);
2484                         if (IS_ERR(ext)) {
2485                                 LASSERT(tmp == grants);
2486                                 osc_exit_cache(cli, oap);
2487                                 rc = PTR_ERR(ext);
2488                                 ext = NULL;
2489                         } else {
2490                                 oio->oi_active = ext;
2491                         }
2492                 }
2493                 if (grants > 0)
2494                         osc_unreserve_grant(cli, grants, tmp);
2495         }
2496
2497         LASSERT(ergo(rc == 0, ext != NULL));
2498         if (ext != NULL) {
2499                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2500                          ext, "index = %lu.\n", index);
2501                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2502
2503                 osc_object_lock(osc);
2504                 if (ext->oe_nr_pages == 0)
2505                         ext->oe_srvlock = ops->ops_srvlock;
2506                 else
2507                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2508                 ++ext->oe_nr_pages;
2509                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2510                 osc_object_unlock(osc);
2511
2512                 if (!ext->oe_layout_version)
2513                         ext->oe_layout_version = io->ci_layout_version;
2514         }
2515
2516         RETURN(rc);
2517 }
2518
2519 int osc_teardown_async_page(const struct lu_env *env,
2520                             struct osc_object *obj, struct osc_page *ops)
2521 {
2522         struct osc_async_page *oap = &ops->ops_oap;
2523         int rc = 0;
2524         ENTRY;
2525
2526         LASSERT(oap->oap_magic == OAP_MAGIC);
2527
2528         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2529                oap, ops, osc_index(oap2osc(oap)));
2530
2531         if (!list_empty(&oap->oap_rpc_item)) {
2532                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2533                 rc = -EBUSY;
2534         } else if (!list_empty(&oap->oap_pending_item)) {
2535                 struct osc_extent *ext = NULL;
2536
2537                 osc_object_lock(obj);
2538                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2539                 osc_object_unlock(obj);
2540                 /* only truncated pages are allowed to be taken out.
2541                  * See osc_extent_truncate() and osc_cache_truncate_start()
2542                  * for details. */
2543                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2544                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2545                                         osc_index(oap2osc(oap)));
2546                         rc = -EBUSY;
2547                 }
2548                 if (ext != NULL)
2549                         osc_extent_put(env, ext);
2550         }
2551         RETURN(rc);
2552 }
2553
2554 /**
2555  * This is called when a page is picked up by kernel to write out.
2556  *
2557  * We should find out the corresponding extent and add the whole extent
2558  * into urgent list. The extent may be being truncated or used, handle it
2559  * carefully.
2560  */
2561 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2562                          struct osc_page *ops)
2563 {
2564         struct osc_extent *ext   = NULL;
2565         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2566         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2567         pgoff_t            index = osc_index(ops);
2568         struct osc_async_page *oap = &ops->ops_oap;
2569         bool unplug = false;
2570         int rc = 0;
2571         ENTRY;
2572
2573         osc_object_lock(obj);
2574         ext = osc_extent_lookup(obj, index);
2575         if (ext == NULL) {
2576                 osc_extent_tree_dump(D_ERROR, obj);
2577                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2578         }
2579
2580         switch (ext->oe_state) {
2581         case OES_RPC:
2582         case OES_LOCK_DONE:
2583                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2584                 LASSERT(0);
2585                 break;
2586         case OES_LOCKING:
2587                 /* If we know this extent is being written out, we should abort
2588                  * so that the writer can make this page ready. Otherwise, there
2589                  * exists a deadlock problem because other process can wait for
2590                  * page writeback bit holding page lock; and meanwhile in
2591                  * vvp_page_make_ready(), we need to grab page lock before
2592                  * really sending the RPC. */
2593         case OES_TRUNC:
2594                 /* race with truncate, page will be redirtied */
2595         case OES_ACTIVE:
2596                 /* The extent is active so we need to abort and let the caller
2597                  * re-dirty the page. If we continued on here, and we were the
2598                  * one making the extent active, we could deadlock waiting for
2599                  * the page writeback to clear but it won't because the extent
2600                  * is active and won't be written out. */
2601                 GOTO(out, rc = -EAGAIN);
2602         default:
2603                 break;
2604         }
2605
2606         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2607         if (rc)
2608                 GOTO(out, rc);
2609
2610         spin_lock(&oap->oap_lock);
2611         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2612         spin_unlock(&oap->oap_lock);
2613
2614         if (memory_pressure_get())
2615                 ext->oe_memalloc = 1;
2616
2617         ext->oe_urgent = 1;
2618         if (ext->oe_state == OES_CACHE) {
2619                 OSC_EXTENT_DUMP(D_CACHE, ext,
2620                                 "flush page %p make it urgent.\n", oap);
2621                 if (list_empty(&ext->oe_link))
2622                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2623                 unplug = true;
2624         }
2625         rc = 0;
2626         EXIT;
2627
2628 out:
2629         osc_object_unlock(obj);
2630         osc_extent_put(env, ext);
2631         if (unplug)
2632                 osc_io_unplug_async(env, osc_cli(obj), obj);
2633         return rc;
2634 }
2635
2636 /**
2637  * this is called when a sync waiter receives an interruption.  Its job is to
2638  * get the caller woken as soon as possible.  If its page hasn't been put in an
2639  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2640  * desiring interruption which will forcefully complete the rpc once the rpc
2641  * has timed out.
2642  */
2643 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2644 {
2645         struct osc_async_page *oap = &ops->ops_oap;
2646         struct osc_object     *obj = oap->oap_obj;
2647         struct client_obd     *cli = osc_cli(obj);
2648         struct osc_extent     *ext;
2649         struct osc_extent     *found = NULL;
2650         struct list_head            *plist;
2651         pgoff_t index = osc_index(ops);
2652         int     rc = -EBUSY;
2653         int     cmd;
2654         ENTRY;
2655
2656         LASSERT(!oap->oap_interrupted);
2657         oap->oap_interrupted = 1;
2658
2659         /* Find out the caching extent */
2660         osc_object_lock(obj);
2661         if (oap->oap_cmd & OBD_BRW_WRITE) {
2662                 plist = &obj->oo_urgent_exts;
2663                 cmd   = OBD_BRW_WRITE;
2664         } else {
2665                 plist = &obj->oo_reading_exts;
2666                 cmd   = OBD_BRW_READ;
2667         }
2668         list_for_each_entry(ext, plist, oe_link) {
2669                 if (ext->oe_start <= index && ext->oe_end >= index) {
2670                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2671                         /* For OES_LOCK_DONE state extent, it has already held
2672                          * a refcount for RPC. */
2673                         found = osc_extent_get(ext);
2674                         break;
2675                 }
2676         }
2677         if (found != NULL) {
2678                 list_del_init(&found->oe_link);
2679                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2680                 osc_object_unlock(obj);
2681
2682                 osc_extent_finish(env, found, 0, -EINTR);
2683                 osc_extent_put(env, found);
2684                 rc = 0;
2685         } else {
2686                 osc_object_unlock(obj);
2687                 /* ok, it's been put in an rpc. only one oap gets a request
2688                  * reference */
2689                 if (oap->oap_request != NULL) {
2690                         ptlrpc_mark_interrupted(oap->oap_request);
2691                         ptlrpcd_wake(oap->oap_request);
2692                         ptlrpc_req_finished(oap->oap_request);
2693                         oap->oap_request = NULL;
2694                 }
2695         }
2696
2697         osc_list_maint(cli, obj);
2698         RETURN(rc);
2699 }
2700
2701 int osc_queue_sync_pages(const struct lu_env *env, const struct cl_io *io,
2702                          struct osc_object *obj, struct list_head *list,
2703                          int brw_flags)
2704 {
2705         struct client_obd     *cli = osc_cli(obj);
2706         struct osc_extent     *ext;
2707         struct osc_async_page *oap;
2708         int     page_count = 0;
2709         int     mppr       = cli->cl_max_pages_per_rpc;
2710         bool    can_merge   = true;
2711         pgoff_t start      = CL_PAGE_EOF;
2712         pgoff_t end        = 0;
2713         ENTRY;
2714
2715         list_for_each_entry(oap, list, oap_pending_item) {
2716                 struct osc_page *opg = oap2osc_page(oap);
2717                 pgoff_t index = osc_index(opg);
2718
2719                 if (index > end)
2720                         end = index;
2721                 if (index < start)
2722                         start = index;
2723                 ++page_count;
2724                 mppr <<= (page_count > mppr);
2725
2726                 if (unlikely(opg->ops_from > 0 || opg->ops_to < PAGE_SIZE))
2727                         can_merge = false;
2728         }
2729
2730         ext = osc_extent_alloc(obj);
2731         if (ext == NULL) {
2732                 struct osc_async_page *tmp;
2733
2734                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2735                         list_del_init(&oap->oap_pending_item);
2736                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2737                 }
2738                 RETURN(-ENOMEM);
2739         }
2740
2741         ext->oe_rw = !!(brw_flags & OBD_BRW_READ);
2742         ext->oe_sync = 1;
2743         ext->oe_no_merge = !can_merge;
2744         ext->oe_urgent = 1;
2745         ext->oe_start = start;
2746         ext->oe_end = ext->oe_max_end = end;
2747         ext->oe_obj = obj;
2748         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2749         ext->oe_ndelay = !!(brw_flags & OBD_BRW_NDELAY);
2750         ext->oe_nr_pages = page_count;
2751         ext->oe_mppr = mppr;
2752         list_splice_init(list, &ext->oe_pages);
2753         ext->oe_layout_version = io->ci_layout_version;
2754
2755         osc_object_lock(obj);
2756         /* Reuse the initial refcount for RPC, don't drop it */
2757         osc_extent_state_set(ext, OES_LOCK_DONE);
2758         if (!ext->oe_rw) { /* write */
2759                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2760                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2761         } else {
2762                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2763                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2764         }
2765         osc_object_unlock(obj);
2766
2767         osc_io_unplug_async(env, cli, obj);
2768         RETURN(0);
2769 }
2770
2771 /**
2772  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2773  */
2774 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2775                              __u64 size, struct osc_extent **extp)
2776 {
2777         struct client_obd *cli = osc_cli(obj);
2778         struct osc_extent *ext;
2779         struct osc_extent *waiting = NULL;
2780         pgoff_t index;
2781         struct list_head list = LIST_HEAD_INIT(list);
2782         int result = 0;
2783         bool partial;
2784         ENTRY;
2785
2786         /* pages with index greater or equal to index will be truncated. */
2787         index = cl_index(osc2cl(obj), size);
2788         partial = size > cl_offset(osc2cl(obj), index);
2789
2790 again:
2791         osc_object_lock(obj);
2792         ext = osc_extent_search(obj, index);
2793         if (ext == NULL)
2794                 ext = first_extent(obj);
2795         else if (ext->oe_end < index)
2796                 ext = next_extent(ext);
2797         while (ext != NULL) {
2798                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2799
2800                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2801                         /* if ext is in urgent state, it means there must exist
2802                          * a page already having been flushed by write_page().
2803                          * We have to wait for this extent because we can't
2804                          * truncate that page. */
2805                         OSC_EXTENT_DUMP(D_CACHE, ext,
2806                                         "waiting for busy extent\n");
2807                         waiting = osc_extent_get(ext);
2808                         break;
2809                 }
2810
2811                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2812
2813                 osc_extent_get(ext);
2814                 if (ext->oe_state == OES_ACTIVE) {
2815                         /* though we grab inode mutex for write path, but we
2816                          * release it before releasing extent(in osc_io_end()),
2817                          * so there is a race window that an extent is still
2818                          * in OES_ACTIVE when truncate starts. */
2819                         LASSERT(!ext->oe_trunc_pending);
2820                         ext->oe_trunc_pending = 1;
2821                 } else {
2822                         EASSERT(ext->oe_state == OES_CACHE, ext);
2823                         osc_extent_state_set(ext, OES_TRUNC);
2824                         osc_update_pending(obj, OBD_BRW_WRITE,
2825                                            -ext->oe_nr_pages);
2826                 }
2827                 /* This extent could be on the full extents list, that's OK */
2828                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2829                 if (!list_empty(&ext->oe_link))
2830                         list_move_tail(&ext->oe_link, &list);
2831                 else
2832                         list_add_tail(&ext->oe_link, &list);
2833
2834                 ext = next_extent(ext);
2835         }
2836         osc_object_unlock(obj);
2837
2838         osc_list_maint(cli, obj);
2839
2840         while (!list_empty(&list)) {
2841                 int rc;
2842
2843                 ext = list_entry(list.next, struct osc_extent, oe_link);
2844                 list_del_init(&ext->oe_link);
2845
2846                 /* extent may be in OES_ACTIVE state because inode mutex
2847                  * is released before osc_io_end() in file write case */
2848                 if (ext->oe_state != OES_TRUNC)
2849                         osc_extent_wait(env, ext, OES_TRUNC);
2850
2851                 rc = osc_extent_truncate(ext, index, partial);
2852                 if (rc < 0) {
2853                         if (result == 0)
2854                                 result = rc;
2855
2856                         OSC_EXTENT_DUMP(D_ERROR, ext,
2857                                         "truncate error %d\n", rc);
2858                 } else if (ext->oe_nr_pages == 0) {
2859                         osc_extent_remove(ext);
2860                 } else {
2861                         /* this must be an overlapped extent which means only
2862                          * part of pages in this extent have been truncated.
2863                          */
2864                         EASSERTF(ext->oe_start <= index, ext,
2865                                  "trunc index = %lu/%d.\n", index, partial);
2866                         /* fix index to skip this partially truncated extent */
2867                         index = ext->oe_end + 1;
2868                         partial = false;
2869
2870                         /* we need to hold this extent in OES_TRUNC state so
2871                          * that no writeback will happen. This is to avoid
2872                          * BUG 17397.
2873                          * Only partial truncate can reach here, if @size is
2874                          * not zero, the caller should provide a valid @extp. */
2875                         LASSERT(*extp == NULL);
2876                         *extp = osc_extent_get(ext);
2877                         OSC_EXTENT_DUMP(D_CACHE, ext,
2878                                         "trunc at %llu\n", size);
2879                 }
2880                 osc_extent_put(env, ext);
2881         }
2882         if (waiting != NULL) {
2883                 int rc;
2884
2885                 /* ignore the result of osc_extent_wait the write initiator
2886                  * should take care of it. */
2887                 rc = osc_extent_wait(env, waiting, OES_INV);
2888                 if (rc < 0)
2889                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2890
2891                 osc_extent_put(env, waiting);
2892                 waiting = NULL;
2893                 goto again;
2894         }
2895         RETURN(result);
2896 }
2897 EXPORT_SYMBOL(osc_cache_truncate_start);
2898
2899 /**
2900  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2901  */
2902 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2903 {
2904         if (ext != NULL) {
2905                 struct osc_object *obj = ext->oe_obj;
2906                 bool unplug = false;
2907
2908                 EASSERT(ext->oe_nr_pages > 0, ext);
2909                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2910                 EASSERT(!ext->oe_urgent, ext);
2911
2912                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2913                 osc_object_lock(obj);
2914                 osc_extent_state_set(ext, OES_CACHE);
2915                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2916                         ext->oe_urgent = 1;
2917                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2918                         unplug = true;
2919                 }
2920                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2921                 osc_object_unlock(obj);
2922                 osc_extent_put(env, ext);
2923
2924                 if (unplug)
2925                         osc_io_unplug_async(env, osc_cli(obj), obj);
2926         }
2927 }
2928
2929 /**
2930  * Wait for extents in a specific range to be written out.
2931  * The caller must have called osc_cache_writeback_range() to issue IO
2932  * otherwise it will take a long time for this function to finish.
2933  *
2934  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2935  * nobody else can dirty this range of file while we're waiting for
2936  * extents to be written.
2937  */
2938 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2939                          pgoff_t start, pgoff_t end)
2940 {
2941         struct osc_extent *ext;
2942         pgoff_t index = start;
2943         int     result = 0;
2944         ENTRY;
2945
2946 again:
2947         osc_object_lock(obj);
2948         ext = osc_extent_search(obj, index);
2949         if (ext == NULL)
2950                 ext = first_extent(obj);
2951         else if (ext->oe_end < index)
2952                 ext = next_extent(ext);
2953         while (ext != NULL) {
2954                 int rc;
2955
2956                 if (ext->oe_start > end)
2957                         break;
2958
2959                 if (!ext->oe_fsync_wait) {
2960                         ext = next_extent(ext);
2961                         continue;
2962                 }
2963
2964                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2965                              ext->oe_hp || ext->oe_urgent), ext);
2966                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2967                              !ext->oe_hp && ext->oe_urgent), ext);
2968
2969                 index = ext->oe_end + 1;
2970                 osc_extent_get(ext);
2971                 osc_object_unlock(obj);
2972
2973                 rc = osc_extent_wait(env, ext, OES_INV);
2974                 if (result == 0)
2975                         result = rc;
2976                 osc_extent_put(env, ext);
2977                 goto again;
2978         }
2979         osc_object_unlock(obj);
2980
2981         OSC_IO_DEBUG(obj, "sync file range.\n");
2982         RETURN(result);
2983 }
2984 EXPORT_SYMBOL(osc_cache_wait_range);
2985
2986 /**
2987  * Called to write out a range of osc object.
2988  *
2989  * @hp     : should be set this is caused by lock cancel;
2990  * @discard: is set if dirty pages should be dropped - file will be deleted or
2991  *         truncated, this implies there is no partially discarding extents.
2992  *
2993  * Return how many pages will be issued, or error code if error occurred.
2994  */
2995 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2996                               pgoff_t start, pgoff_t end, int hp, int discard)
2997 {
2998         struct osc_extent *ext;
2999         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
3000         bool unplug = false;
3001         int result = 0;
3002         ENTRY;
3003
3004         osc_object_lock(obj);
3005         ext = osc_extent_search(obj, start);
3006         if (ext == NULL)
3007                 ext = first_extent(obj);
3008         else if (ext->oe_end < start)
3009                 ext = next_extent(ext);
3010         while (ext != NULL) {
3011                 if (ext->oe_start > end)
3012                         break;
3013
3014                 ext->oe_fsync_wait = 1;
3015                 switch (ext->oe_state) {
3016                 case OES_CACHE:
3017                         result += ext->oe_nr_pages;
3018                         if (!discard) {
3019                                 struct list_head *list = NULL;
3020                                 if (hp) {
3021                                         EASSERT(!ext->oe_hp, ext);
3022                                         ext->oe_hp = 1;
3023                                         list = &obj->oo_hp_exts;
3024                                 } else if (!ext->oe_urgent) {
3025                                         ext->oe_urgent = 1;
3026                                         list = &obj->oo_urgent_exts;
3027                                 }
3028                                 if (list != NULL)
3029                                         list_move_tail(&ext->oe_link, list);
3030                                 unplug = true;
3031                         } else {
3032                                 /* the only discarder is lock cancelling, so
3033                                  * [start, end] must contain this extent */
3034                                 EASSERT(ext->oe_start >= start &&
3035                                         ext->oe_max_end <= end, ext);
3036                                 osc_extent_state_set(ext, OES_LOCKING);
3037                                 ext->oe_owner = current;
3038                                 list_move_tail(&ext->oe_link,
3039                                                    &discard_list);
3040                                 osc_update_pending(obj, OBD_BRW_WRITE,
3041                                                    -ext->oe_nr_pages);
3042                         }
3043                         break;
3044                 case OES_ACTIVE:
3045                         /* It's pretty bad to wait for ACTIVE extents, because
3046                          * we don't know how long we will wait for it to be
3047                          * flushed since it may be blocked at awaiting more
3048                          * grants. We do this for the correctness of fsync. */
3049                         LASSERT(hp == 0 && discard == 0);
3050                         ext->oe_urgent = 1;
3051                         break;
3052                 case OES_TRUNC:
3053                         /* this extent is being truncated, can't do anything
3054                          * for it now. it will be set to urgent after truncate
3055                          * is finished in osc_cache_truncate_end(). */
3056                 default:
3057                         break;
3058                 }
3059                 ext = next_extent(ext);
3060         }
3061         osc_object_unlock(obj);
3062
3063         LASSERT(ergo(!discard, list_empty(&discard_list)));
3064         if (!list_empty(&discard_list)) {
3065                 struct osc_extent *tmp;
3066                 int rc;
3067
3068                 osc_list_maint(osc_cli(obj), obj);
3069                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
3070                         list_del_init(&ext->oe_link);
3071                         EASSERT(ext->oe_state == OES_LOCKING, ext);
3072
3073                         /* Discard caching pages. We don't actually write this
3074                          * extent out but we complete it as if we did. */
3075                         rc = osc_extent_make_ready(env, ext);
3076                         if (unlikely(rc < 0)) {
3077                                 OSC_EXTENT_DUMP(D_ERROR, ext,
3078                                                 "make_ready returned %d\n", rc);
3079                                 if (result >= 0)
3080                                         result = rc;
3081                         }
3082
3083                         /* finish the extent as if the pages were sent */
3084                         osc_extent_finish(env, ext, 0, 0);
3085                 }
3086         }
3087
3088         if (unplug)
3089                 osc_io_unplug(env, osc_cli(obj), obj);
3090
3091         if (hp || discard) {
3092                 int rc;
3093                 rc = osc_cache_wait_range(env, obj, start, end);
3094                 if (result >= 0 && rc < 0)
3095                         result = rc;
3096         }
3097
3098         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
3099         RETURN(result);
3100 }
3101 EXPORT_SYMBOL(osc_cache_writeback_range);
3102
3103 /**
3104  * Returns a list of pages by a given [start, end] of \a obj.
3105  *
3106  * \param resched If not NULL, then we give up before hogging CPU for too
3107  * long and set *resched = 1, in that case caller should implement a retry
3108  * logic.
3109  *
3110  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
3111  * crucial in the face of [offset, EOF] locks.
3112  *
3113  * Return at least one page in @queue unless there is no covered page.
3114  */
3115 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3116                         struct osc_object *osc, pgoff_t start, pgoff_t end,
3117                         osc_page_gang_cbt cb, void *cbdata)
3118 {
3119         struct osc_page *ops;
3120         struct pagevec  *pagevec;
3121         void            **pvec;
3122         pgoff_t         idx;
3123         unsigned int    nr;
3124         unsigned int    i;
3125         unsigned int    j;
3126         int             res = CLP_GANG_OKAY;
3127         bool            tree_lock = true;
3128         ENTRY;
3129
3130         idx = start;
3131         pvec = osc_env_info(env)->oti_pvec;
3132         pagevec = &osc_env_info(env)->oti_pagevec;
3133         ll_pagevec_init(pagevec, 0);
3134         spin_lock(&osc->oo_tree_lock);
3135         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3136                                             idx, OTI_PVEC_SIZE)) > 0) {
3137                 struct cl_page *page;
3138                 bool end_of_region = false;
3139
3140                 for (i = 0, j = 0; i < nr; ++i) {
3141                         ops = pvec[i];
3142                         pvec[i] = NULL;
3143
3144                         idx = osc_index(ops);
3145                         if (idx > end) {
3146                                 end_of_region = true;
3147                                 break;
3148                         }
3149
3150                         page = ops->ops_cl.cpl_page;
3151                         LASSERT(page->cp_type == CPT_CACHEABLE);
3152                         if (page->cp_state == CPS_FREEING)
3153                                 continue;
3154
3155                         cl_page_get(page);
3156                         lu_ref_add_atomic(&page->cp_reference,
3157                                           "gang_lookup", current);
3158                         pvec[j++] = ops;
3159                 }
3160                 ++idx;
3161
3162                 /*
3163                  * Here a delicate locking dance is performed. Current thread
3164                  * holds a reference to a page, but has to own it before it
3165                  * can be placed into queue. Owning implies waiting, so
3166                  * radix-tree lock is to be released. After a wait one has to
3167                  * check that pages weren't truncated (cl_page_own() returns
3168                  * error in the latter case).
3169                  */
3170                 spin_unlock(&osc->oo_tree_lock);
3171                 tree_lock = false;
3172